PHP Variable Testing Cheatsheet for PHP 5.0.5

PHP Variable Testing

This page has been generated with PHP 5.0.5

Important notes on the comparisons and tests:

There appear to be two null values at the start of the test. The first one is actually an unset variable, i.e. no longer in existence. The second is a variable which was set to null.
Tests with Ctype and strcmp-type functions use the system default C locale. Results may vary for other locales.
Some tests might seem a bit ‘silly’, for instance testing with === 'null'. The reason for adding these tests can be divided into two categories:
1. Data received from databases and $_POST/$_GET/etc variables are always received as strings (unless a potentially used database abstraction layer changes this). So sometimes testing for a string value where a non-string variable type would be more logical, can actually make sense.
2. Some are unfortunately regularly encountered in code and added here to illustrate why not to use them.
BEWARE: some variable changing functions will not return a changed value, but will return whether the changing succeeded. You will find this indicated in the function header by the use of $copy (as the test will use a copy of the variable to not influence the other tests in the same table).

Notes on some variables:

Some of the test variables used, do not print the way they are set, either because they contain invisible characters or because they result in something else, so for your convenience, these are outlined here:

†	How the variable is defined:
i8	`$x = 0xCC00F9; // Hexadecimal integer.`
i9	`$x = 052; // Octal integer.`
ia	`$x = 0b0111001; // Binary integer (PHP5.4+).`
ib	`$x = ‏௫‏; // Tamil digit five - entered as string as PHP itself cannot deal with it as an integer.`
ic	`$x = ⁸₈; // Unicode superscript and subscript digit 8 - entered as a string as PHP itself cannot deal with these as integers.`
f5	`$x = acos(8); // = NAN`
f6	`$x = NAN; // = Not a number.`
f7	`$x = log(0); // = Infinite.`
f8	`$x = INF; // = Infinite.`
f9	`$x = 1.2345E8; // Exponent notation float.`
fa	`$x = ⅕; // Unicode character representing 1/5 - entered as string as PHP itself cannot deal with it as a float.`
sk	`$x = "123, \"str\"\r\n";`
sn	`$x = "\f\t\r\n";`
sp	`$x = "\x7f\t\r\n"`

Legend / How to use the tables:

The error level for this test sheet has been set to E_ALL & ~E_STRICT. All errors are caught and referenced (with #links) in the tables with details of the error messages (if any) below each table. Similar error messages are grouped together for your convenience.
Some column labels have been shortened to avoid them taking undue space. These are indicated by a …. If you mouse-over the column label you will see the full variable/test information.
In comparison tables, the left-top table header will indicate the comparison used and link to the relevant page in the PHP Manual.
In test tables, the left top table header indicates the type of tests. Both this header as well as most column headers link to their respective relevant PHP Manual pages.
A ‡ with a number next to a column header means there is a (linked) footnote for that entry at the bottom of the page.
When you mouse-over the table the row and column you are at are highlighted. To help you compare specific columns/rows, you can click on any cell to mark the column and row which the cell intersects for extra highlighting. Click again to remove this sticky highlight.

Legend to the color coding

NULL:	null
Boolean:	true / false
Integer:	123456789 / 0
Float:	12345.6789
String:	‘A string’
Array and Object:	Indicated as such. Array keys, array values and object properties will be color coded according to the coding shown here.
Resources:	Resource id #44

General typing
is_…()
Null
Boolean
Integers
Floats
Numeric tests
String casting
String tests
Array casting
Array testing
Objects
Resources
Basic Arithmetic
CType Extension

General typing	gettype()	empty()	is_null()	isset()	(bool)	if( $x ) {..}	General typing
General typing	gettype()	empty()	is_null()	isset()	(bool)	if( $x ) {..}	General typing
$x = *null* : ( = NULL )	‘NULL’	true	true	false	false	false	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	‘NULL’	true	true	false	false	false	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	‘boolean’	true	false	true	false	false	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	‘boolean’	false	false	true	true	true	$x = *bool* : 1 ( = true )
$x = *int* : 1	‘integer’	false	false	true	true	true	$x = *int* : 1
$x = *int* : 0	‘integer’	true	false	true	false	false	$x = *int* : 0
$x = *int* : -1	‘integer’	false	false	true	true	true	$x = *int* : -1
$x = *int* : 42	‘integer’	false	false	true	true	true	$x = *int* : 42
^†i8$x = *int* : 13369593	‘integer’	false	false	true	true	true	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	‘integer’	false	false	true	true	true	^†i9$x = *int* : 42
$x = *float* : 1.3	‘double’	false	false	true	true	true	$x = *float* : 1.3
$x = *float* : 0.005	‘double’	false	false	true	true	true	$x = *float* : 0.005
$x = *float* : 0	‘double’	true	false	true	false	false	$x = *float* : 0
$x = *float* : -1.3	‘double’	false	false	true	true	true	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	‘double’	true	false	true	false	false	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	‘double’	true	false	true	false	false	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	‘double’	false	false	true	true	true	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	‘double’	false	false	true	true	true	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	‘string’	true	false	true	false	false	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	‘string’	false	false	true	true	true	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	‘string’	false	false	true	true	true	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	‘string’	false	false	true	true	true	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	‘string’	false	false	true	true	true	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	‘string’	true	false	true	false	false	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	‘string’	false	false	true	true	true	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	‘string’	false	false	true	true	true	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	‘string’	false	false	true	true	true	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	‘string’	false	false	true	true	true	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	‘string’	false	false	true	true	true	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	‘string’	false	false	true	true	true	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	‘string’	false	false	true	true	true	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	‘string’	false	false	true	true	true	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	‘string’	false	false	true	true	true	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	‘string’	false	false	true	true	true	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	‘string’	false	false	true	true	true	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	‘string’	false	false	true	true	true	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	‘string’	false	false	true	true	true	$x = *string[4]* : ‘0123’
$x = array()	‘array’	true	false	true	false	false	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	‘array’	false	false	true	true	true	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	‘array’	false	false	true	true	true	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	‘object’	false	false	true	true	true	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	‘object’	false	false	true	true	true	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #46 ( = RESOURCE )	‘resource’	false	false	true	true	true	$x = *resource* : Resource id #46 ( = RESOURCE )

Notice: Undefined index: notset

is_…()	gettype()	is_null()	is_scalar()	is_bool()	is_int()	is_float()	is_string()	is_array()	is_object()	is_resource()	is_callable()	is_numeric()	is_…()
is_…()	gettype()	is_null()	is_scalar()	is_bool()	is_int()	is_float()	is_string()	is_array()	is_object()	is_resource()	is_callable()	is_numeric()	is_…()
$x = *null* : ( = NULL )	‘NULL’	true	false	false	false	false	false	false	false	false	false	false	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	‘NULL’	true	false	false	false	false	false	false	false	false	false	false	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	‘boolean’	false	true	true	false	false	false	false	false	false	false	false	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	‘boolean’	false	true	true	false	false	false	false	false	false	false	false	$x = *bool* : 1 ( = true )
$x = *int* : 1	‘integer’	false	true	false	true	false	false	false	false	false	false	true	$x = *int* : 1
$x = *int* : 0	‘integer’	false	true	false	true	false	false	false	false	false	false	true	$x = *int* : 0
$x = *int* : -1	‘integer’	false	true	false	true	false	false	false	false	false	false	true	$x = *int* : -1
$x = *int* : 42	‘integer’	false	true	false	true	false	false	false	false	false	false	true	$x = *int* : 42
^†i8$x = *int* : 13369593	‘integer’	false	true	false	true	false	false	false	false	false	false	true	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	‘integer’	false	true	false	true	false	false	false	false	false	false	true	^†i9$x = *int* : 42
$x = *float* : 1.3	‘double’	false	true	false	false	true	false	false	false	false	false	true	$x = *float* : 1.3
$x = *float* : 0.005	‘double’	false	true	false	false	true	false	false	false	false	false	true	$x = *float* : 0.005
$x = *float* : 0	‘double’	false	true	false	false	true	false	false	false	false	false	true	$x = *float* : 0
$x = *float* : -1.3	‘double’	false	true	false	false	true	false	false	false	false	false	true	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	‘double’	false	true	false	false	true	false	false	false	false	false	true	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	‘double’	false	true	false	false	true	false	false	false	false	false	true	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	‘double’	false	true	false	false	true	false	false	false	false	false	true	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	‘double’	false	true	false	false	true	false	false	false	false	false	true	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	‘string’	false	true	false	false	false	true	false	false	false	false	false	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘is_array’	‘string’	false	true	false	false	false	true	false	false	false	true	false	$x = *string[8]* : ‘is_array’
$x = *string[8]* : ‘0xCC00F9’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	‘string’	false	true	false	false	false	true	false	false	false	false	true	$x = *string[4]* : ‘0123’
$x = array()	‘array’	false	false	false	false	false	false	true	false	false	false	false	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	‘array’	false	false	false	false	false	false	true	false	false	false	false	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	‘array’	false	false	false	false	false	false	true	false	false	false	false	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	‘object’	false	false	false	false	false	false	false	true	false	false	false	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	‘object’	false	false	false	false	false	false	false	true	false	false	false	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #49 ( = RESOURCE )	‘resource’	false	false	false	false	false	false	false	false	true	false	false	$x = *resource* : Resource id #49 ( = RESOURCE )

Notice: Undefined index: notset

Null	settype ( $copy, 'null' )	(unset)	unset()	CastToType::_null ( $x ) ^‡1	isset()	empty()	is_null()	== null	=== null	== 'null'	=== 'null'	Null
Null	settype ( $copy, 'null' )	(unset)	unset()	CastToType::_null ( $x ) ^‡1	isset()	empty()	is_null()	== null	=== null	== 'null'	=== 'null'	Null
$x = *null* : ( = NULL )	null	null	null ( #2 )	null	false	true	true	true	true	false	false	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	null	null	null ( #2 )	null	false	true	true	true	true	false	false	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	null	null	null ( #2 )	null	true	true	false	true	false	false	false	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	null	null	null ( #2 )	null	true	false	false	false	false	true	false	$x = *bool* : 1 ( = true )
$x = *int* : 1	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *int* : 1
$x = *int* : 0	null	null	null ( #2 )	null	true	true	false	true	false	true	false	$x = *int* : 0
$x = *int* : -1	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *int* : -1
$x = *int* : 42	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *int* : 42
^†i8$x = *int* : 13369593	null	null	null ( #2 )	null	true	false	false	false	false	false	false	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	null	null	null ( #2 )	null	true	false	false	false	false	false	false	^†i9$x = *int* : 42
$x = *float* : 1.3	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *float* : 1.3
$x = *float* : 0.005	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *float* : 0.005
$x = *float* : 0	null	null	null ( #2 )	null	true	true	false	true	false	true	false	$x = *float* : 0
$x = *float* : -1.3	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	null	null	null ( #2 )	null	true	true	false	true	false	true	false	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	null	null	null ( #2 )	null	true	true	false	true	false	true	false	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	null	null	null ( #2 )	null	true	false	false	false	false	false	false	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	null	null	null ( #2 )	null	true	false	false	false	false	false	false	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	null	null	null ( #2 )	null	true	true	false	true	false	false	false	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	null	null	null ( #2 )	null	true	true	false	false	false	false	false	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	null	null	null ( #2 )	null	true	false	false	false	false	true	true	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *string[4]* : ‘0123’
$x = array()	null	null	null ( #2 )	null	true	true	false	true	false	false	false	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #52 ( = RESOURCE )	null	null	null ( #2 )	null	true	false	false	false	false	false	false	$x = *resource* : Resource id #52 ( = RESOURCE )

Notice: Undefined index: notset
Notice: Undefined variable: x

^{‡ 1}

Uses an external library

Boolean	settype ( $copy, 'bool' )	(bool)	filter_var (…)	filter_var (…) ^‡1 ^‡2	CastToType::_bool ( $x, false, false ) ^‡3	is_bool()	== true	=== true	== 1	== 'true'	== false	=== false	== 0	== 'false'	if( $x ) {..}	if( ! $x ) {..}	Boolean
Boolean	settype ( $copy, 'bool' )	(bool)	filter_var (…)	filter_var (…) ^‡1 ^‡2	CastToType::_bool ( $x, false, false ) ^‡3	is_bool()	== true	=== true	== 1	== 'true'	== false	=== false	== 0	== 'false'	if( $x ) {..}	if( ! $x ) {..}	Boolean
$x = *null* : ( = NULL )	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	true	false	true	false	false	true	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	true	false	true	false	false	true	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	true	false	false	false	false	true	true	true	false	false	true	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	true	true	true	true	true	false	false	false	true	true	false	$x = *bool* : 1 ( = true )
$x = *int* : 1	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	false	true	false	true	false	false	false	false	false	true	false	$x = *int* : 1
$x = *int* : 0	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	false	false	false	true	true	false	true	true	false	true	$x = *int* : 0
$x = *int* : -1	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *int* : -1
$x = *int* : 42	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *int* : 42
^†i8$x = *int* : 13369593	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	^†i9$x = *int* : 42
$x = *float* : 1.3	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *float* : 1.3
$x = *float* : 0.005	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *float* : 0.005
$x = *float* : 0	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	false	false	false	true	true	false	true	true	false	true	$x = *float* : 0
$x = *float* : -1.3	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	true	true	true	false	true	true	false	true	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	false	false	false	true	true	false	true	true	false	true	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	true	false	true	false	false	true	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	true	false	true	false	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	false	true	false	true	false	false	false	false	false	true	false	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	false	true	false	true	false	false	false	false	false	true	false	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	false	false	false	false	true	false	true	false	false	true	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	true	false	true	false	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	false	true	false	false	true	false	false	true	false	true	false	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	true	false	false	false	false	false	true	true	true	false	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	true	false	true	false	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	true	false	true	false	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[10]* : ‘123, "str"’
$x = *string[2]* : ‘on’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	false	true	false	false	false	false	false	true	false	true	false	$x = *string[2]* : ‘on’
$x = *string[3]* : ‘off’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	true	false	false	false	false	false	true	false	true	false	$x = *string[3]* : ‘off’
$x = *string[3]* : ‘yes’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	true	false	true	false	false	false	false	false	true	false	true	false	$x = *string[3]* : ‘yes’
$x = *string[2]* : ‘no’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	false	false	true	false	false	false	false	false	true	false	true	false	$x = *string[2]* : ‘no’
$x = *string[8]* : ‘0xCC00F9’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *string[4]* : ‘0123’
$x = array()	false	false	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	true	false	false	false	false	true	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [1] => null )	false	true	false	false	false	false	false	false	false	true	false	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [0] => b false [1] => b true [2] => null [3] => null [4] => null [5] => null )	false	true	false	false	false	false	false	false	false	true	false	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #99 ( = RESOURCE )	true	true	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	true	false	false	false	false	false	false	false	true	false	$x = *resource* : Resource id #99 ( = RESOURCE )

Notice: Undefined index: notset

^{‡ 1}

Please note: On some PHP versions filter_var( $x, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE ) where $x = false will incorrectly return null.
Also: with the same parameters filter_var() will return false instead of null for most objects.

^{‡ 2}

The code snippet is simplified for brevity. Please refer to the source of this file on GitHub for full details on how to use filter_var_array().

^{‡ 3}

Uses an external library

Integers	settype ( $copy, 'int' )	(int)	intval()	$x + 0	filter_var (…)	filter_var (…) ^‡1	CastToType::_int ( $x, false, false ) ^‡2	abs()	empty()	is_int()	is_numeric()	ctype_digit() ^‡3	preg_match (`^[0-9]+$`)	preg_match (`^[0-9-]+$`)	preg_match (`^[\p{N}-]+$`u)	Integers
Integers	settype ( $copy, 'int' )	(int)	intval()	$x + 0	filter_var (…)	filter_var (…) ^‡1	CastToType::_int ( $x, false, false ) ^‡2	abs()	empty()	is_int()	is_numeric()	ctype_digit() ^‡3	preg_match (`^[0-9]+$`)	preg_match (`^[0-9-]+$`)	preg_match (`^[\p{N}-]+$`u)	Integers
$x = *null* : ( = NULL )	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	true	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	true	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	true	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1	false	false	false	false	true	true	E: not available (PHP 5.1+)	$x = *bool* : 1 ( = true )
$x = *int* : 1	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	1	false	true	true	false	true	true	E: not available (PHP 5.1+)	$x = *int* : 1
$x = *int* : 0	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	0	true	true	true	false	true	true	E: not available (PHP 5.1+)	$x = *int* : 0
$x = *int* : -1	-1	-1	-1	-1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1	1	false	true	true	false	false	true	E: not available (PHP 5.1+)	$x = *int* : -1
$x = *int* : 42	42	42	42	42	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	42	42	false	true	true	false	true	true	E: not available (PHP 5.1+)	$x = *int* : 42
^†i8$x = *int* : 13369593	13369593	13369593	13369593	13369593	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	13369593	13369593	false	true	true	true	true	true	E: not available (PHP 5.1+)	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	42	42	42	42	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	42	42	false	true	true	false	true	true	E: not available (PHP 5.1+)	^†i9$x = *int* : 42
^†ib$x = *string[3]* : ‘௫’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	^†ib$x = *string[3]* : ‘௫’
^†ic$x = *string[6]* : ‘⁸₈’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	^†ic$x = *string[6]* : ‘⁸₈’
$x = *float* : 1.3	1	1	1	1.3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1.3	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *float* : 1.3
$x = *float* : 0.005	0	0	0	0.005	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0.005	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *float* : 0.005
$x = *float* : 0	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	0	true	false	true	false	true	true	E: not available (PHP 5.1+)	$x = *float* : 0
$x = *float* : -1.3	-1	-1	-1	-1.3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1.3	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	0	0	0	-1.#IND	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1.#QNAN	true	false	true	false	false	false	E: not available (PHP 5.1+)	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	0	true	false	true	false	true	true	E: not available (PHP 5.1+)	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	0	0	0	-1.#INF	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1.#INF	false	false	true	false	false	false	E: not available (PHP 5.1+)	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	123450000	123450000	123450000	123450000	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	123450000	123450000	false	false	true	false	true	true	E: not available (PHP 5.1+)	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	true	false	false	true	false	false	E: not available (PHP 5.1+)	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	1	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	3	3	3	3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	3	3	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	1	false	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	0	true	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	-1	-1	-1	-1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1	1	false	false	true	false	false	true	E: not available (PHP 5.1+)	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	42	42	42	42	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	42	42	false	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	1	1	1	1.3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1.3	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	-1	-1	-1	-1.305	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	1.305	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	123	123	123	123	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	123	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	0	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	123	123	123	123	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	123	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	0	0	0	13369593	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	13369593	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	123	123	123	123	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	123	123	false	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[4]* : ‘0123’
$x = array()	0	0	0	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	b false	true	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	1	1	1	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [1] => null )	b false	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	1	1	1	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [0] => null [1] => 1 [2] => null [3] => null [4] => null [5] => null )	b false	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	b false	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	b false	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #149 ( = RESOURCE )	149	149	149	149	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	149	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = *resource* : Resource id #149 ( = RESOURCE )

Notice: Undefined index: notset
Fatal error: Unsupported operand types
Warning: preg_match() expects parameter 2 to be string, array/object/resource given

^{‡ 1}

The code snippet is simplified for brevity. Please refer to the source of this file on GitHub for full details on how to use filter_var_array().

^{‡ 2}

Uses an external library

^{‡ 3}

Important: Integers between -128 and 255 are interpreted as the ASCII value pointing to a character (negative values have 256 added in order to allow characters in the Extended ASCII range).
In any other case, integers are interpreted as a string containing the decimal digits of the integer.

Floats	settype ( $copy, 'float' )	(float)	floatval()	$x + 0.0	filter_var (…)	filter_var (…) ^‡1	CastToType::_float ( $x, false, false ) ^‡2	empty()	is_float()	is_numeric()	ctype_digit() ^‡3	preg_match (`^[0-9\.]+$`)	preg_match (`^[0-9\.-]+$`)	preg_match (`^[\p{N}\.-]+$`u)	Floats
Floats	settype ( $copy, 'float' )	(float)	floatval()	$x + 0.0	filter_var (…)	filter_var (…) ^‡1	CastToType::_float ( $x, false, false ) ^‡2	empty()	is_float()	is_numeric()	ctype_digit() ^‡3	preg_match (`^[0-9\.]+$`)	preg_match (`^[0-9\.-]+$`)	preg_match (`^[\p{N}\.-]+$`u)	Floats
$x = *null* : ( = NULL )	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	true	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	true	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	true	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	false	false	false	false	true	true	E: not available (PHP 5.1+)	$x = *bool* : 1 ( = true )
$x = *int* : 1	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	false	false	true	false	true	true	E: not available (PHP 5.1+)	$x = *int* : 1
$x = *int* : 0	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	true	false	true	false	true	true	E: not available (PHP 5.1+)	$x = *int* : 0
$x = *int* : -1	-1	-1	-1	-1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1	false	false	true	false	false	true	E: not available (PHP 5.1+)	$x = *int* : -1
$x = *int* : 42	42	42	42	42	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	42	false	false	true	false	true	true	E: not available (PHP 5.1+)	$x = *int* : 42
^†i8$x = *int* : 13369593	13369593	13369593	13369593	13369593	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	13369593	false	false	true	true	true	true	E: not available (PHP 5.1+)	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	42	42	42	42	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	42	false	false	true	false	true	true	E: not available (PHP 5.1+)	^†i9$x = *int* : 42
$x = *float* : 1.3	1.3	1.3	1.3	1.3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1.3	false	true	true	false	true	true	E: not available (PHP 5.1+)	$x = *float* : 1.3
$x = *float* : 0.005	0.005	0.005	0.005	0.005	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0.005	false	true	true	false	true	true	E: not available (PHP 5.1+)	$x = *float* : 0.005
$x = *float* : 0	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	true	true	true	false	true	true	E: not available (PHP 5.1+)	$x = *float* : 0
$x = *float* : -1.3	-1.3	-1.3	-1.3	-1.3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1.3	false	true	true	false	false	true	E: not available (PHP 5.1+)	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1.#IND	true	true	true	false	false	false	E: not available (PHP 5.1+)	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	true	true	true	false	true	true	E: not available (PHP 5.1+)	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	-1.#INF	-1.#INF	-1.#INF	-1.#INF	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1.#INF	false	true	true	false	false	false	E: not available (PHP 5.1+)	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	123450000	123450000	123450000	123450000	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	123450000	false	true	true	false	true	true	E: not available (PHP 5.1+)	^†f9$x = *float* : 123450000
^†fa$x = *string[3]* : ‘⅕’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	^†fa$x = *string[3]* : ‘⅕’
$x = *string[0]* : ‘’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	true	false	false	true	false	false	E: not available (PHP 5.1+)	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	3	3	3	3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	3	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	1	1	1	1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1	false	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	true	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	-1	-1	-1	-1	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1	false	false	true	false	false	true	E: not available (PHP 5.1+)	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	42	42	42	42	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	42	false	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	1.3	1.3	1.3	1.3	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	1.3	false	false	true	false	true	true	E: not available (PHP 5.1+)	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	0	false	false	true	false	true	true	E: not available (PHP 5.1+)	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	-1.305	-1.305	-1.305	-1.305	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	-1.305	false	false	true	false	false	true	E: not available (PHP 5.1+)	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	123	123	123	123	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	0	0	0	0	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	123	123	123	123	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	false	false	E: not available (PHP 5.1+)	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	0	0	0	13369593	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	true	false	false	false	E: not available (PHP 5.1+)	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	123	123	123	123	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	123	false	false	true	true	true	true	E: not available (PHP 5.1+)	$x = *string[4]* : ‘0123’
$x = array()	0	0	0	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	true	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	1	1	1	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [1] => null )	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	1	1	1	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [0] => null [1] => 1 [2] => 1.3 [3] => null [4] => null [5] => null )	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	1 ( #4 )	1 ( #4 )	1 ( #4 )	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	1 ( #4 )	1 ( #4 )	1 ( #4 )	Fatal error ( #2 )	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #197 ( = RESOURCE )	197	197	197	197	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	false	false	false	false	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	$x = *resource* : Resource id #197 ( = RESOURCE )

Notice: Undefined index: notset
Fatal error: Unsupported operand types
Warning: preg_match() expects parameter 2 to be string, array/object/resource given
Notice: Object of class stdClass/TestObject/TestObjectToString could not be converted to double

^{‡ 1}

The code snippet is simplified for brevity. Please refer to the source of this file on GitHub for full details on how to use filter_var_array().

^{‡ 2}

Uses an external library

^{‡ 3}

Numeric tests	is_numeric()	ctype_digit() ^‡1	preg_match (`^[\p{N}-]+$`u)	preg_match (`^[\p{N}\.-]+$`u)	> 0	>= 0	== 0	=== 0	!= 0	!== 0	< 0	<= 0	is_nan()	is_finite()	is_infinite()	floor()	ceil()	round()	Numeric tests
Numeric tests	is_numeric()	ctype_digit() ^‡1	preg_match (`^[\p{N}-]+$`u)	preg_match (`^[\p{N}\.-]+$`u)	> 0	>= 0	== 0	=== 0	!= 0	!== 0	< 0	<= 0	is_nan()	is_finite()	is_infinite()	floor()	ceil()	round()	Numeric tests
$x = *null* : ( = NULL )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	1	1	1	$x = *bool* : 1 ( = true )
$x = *int* : 1	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	1	1	1	$x = *int* : 1
$x = *int* : 0	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	true	false	false	false	true	false	true	false	0	0	0	$x = *int* : 0
$x = *int* : -1	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	false	false	false	true	true	true	true	false	true	false	-1	-1	-1	$x = *int* : -1
$x = *int* : 42	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	42	42	42	$x = *int* : 42
^†i8$x = *int* : 13369593	true	true	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	13369593	13369593	13369593	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	42	42	42	^†i9$x = *int* : 42
^†ib$x = *string[3]* : ‘௫’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	^†ib$x = *string[3]* : ‘௫’
^†ic$x = *string[6]* : ‘⁸₈’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	^†ic$x = *string[6]* : ‘⁸₈’
$x = *float* : 1.3	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	1	2	1	$x = *float* : 1.3
$x = *float* : 0.005	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	0	1	0	$x = *float* : 0.005
$x = *float* : 0	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	$x = *float* : 0
$x = *float* : -1.3	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	false	false	false	true	true	true	true	false	true	false	-2	-1	-1	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	true	false	false	-1.#IND	-1.#IND	-1.#IND	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	false	false	false	true	true	true	true	false	false	true	-1.#INF	-1.#INF	-1.#INF	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	123450000	123450000	123450000	^†f9$x = *float* : 123450000
^†fa$x = *string[3]* : ‘⅕’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	^†fa$x = *string[3]* : ‘⅕’
$x = *string[0]* : ‘’	false	true	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	1	1	1	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	3	3	3	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	true	true	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	1	1	1	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	true	true	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	false	false	false	true	true	true	true	false	true	false	-1	-1	-1	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	true	true	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	42	42	42	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	1	2	1	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	false	true	false	0	0	0	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	false	false	false	true	true	true	true	false	true	false	-2	-1	-1	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	123	123	123	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	false	true	true	false	false	true	false	true	null ( #2 )	null ( #3 )	null ( #4 )	0	0	0	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	123	123	123	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	true	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	13369593	13369593	13369593	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	true	true	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	false	true	false	123	123	123	$x = *string[4]* : ‘0123’
$x = array()	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	b false	b false	b false	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	b false	b false	b false	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	b false	b false	b false	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	b false	b false	b false	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	b false	b false	b false	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #244 ( = RESOURCE )	false	false	E: not available (PHP 5.1+)	E: not available (PHP 5.1+)	true	true	false	false	true	true	false	false	null ( #2 )	null ( #3 )	null ( #4 )	244	244	244	$x = *resource* : Resource id #244 ( = RESOURCE )

Notice: Undefined index: notset
Warning: is_nan() expects parameter 1 to be double, string/array/object/resource given
Warning: is_finite() expects parameter 1 to be double, string/array/object/resource given
Warning: is_infinite() expects parameter 1 to be double, string/array/object/resource given

^{‡ 1}

String casting	settype ( $copy, 'string' ) ^‡1 ^‡2	(string)	strval()	$x . ''	filter_var (…)	filter_var (…) ^‡3	CastToType::_string ( $x, false, false ) ^‡4	String casting
String casting	settype ( $copy, 'string' ) ^‡1 ^‡2	(string)	strval()	$x . ''	filter_var (…)	filter_var (…) ^‡3	CastToType::_string ( $x, false, false ) ^‡4	String casting
$x = *null* : ( = NULL )	‘’	‘’	‘’	‘ ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	‘’	‘’	‘’	‘ ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	‘’	‘’	‘’	‘ ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	‘1’	‘1’	‘1’	‘1 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = *bool* : 1 ( = true )
$x = *int* : 1	‘1’	‘1’	‘1’	‘1 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘1’	$x = *int* : 1
$x = *int* : 0	‘0’	‘0’	‘0’	‘0 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0’	$x = *int* : 0
$x = *int* : -1	‘-1’	‘-1’	‘-1’	‘-1 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘-1’	$x = *int* : -1
$x = *int* : 42	‘42’	‘42’	‘42’	‘42 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘42’	$x = *int* : 42
^†i8$x = *int* : 13369593	‘13369593’	‘13369593’	‘13369593’	‘13369593 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘13369593’	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	‘42’	‘42’	‘42’	‘42 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘42’	^†i9$x = *int* : 42
$x = *float* : 1.3	‘1.3’	‘1.3’	‘1.3’	‘1.3 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘1.3’	$x = *float* : 1.3
$x = *float* : 0.005	‘0.005’	‘0.005’	‘0.005’	‘0.005 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0.005’	$x = *float* : 0.005
$x = *float* : 0	‘0’	‘0’	‘0’	‘0 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0’	$x = *float* : 0
$x = *float* : -1.3	‘-1.3’	‘-1.3’	‘-1.3’	‘-1.3 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘-1.3’	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	‘-1.#IND’	‘-1.#IND’	‘-1.#IND’	‘-1.#IND ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘-1.#IND’	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	‘0’	‘0’	‘0’	‘0 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0’	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	‘-1.#INF’	‘-1.#INF’	‘-1.#INF’	‘-1.#INF ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘-1.#INF’	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	‘123450000’	‘123450000’	‘123450000’	‘123450000 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘123450000’	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	‘’	‘’	‘’	‘ ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	‘ ’	‘ ’	‘ ’	‘ ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘ ’	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	‘ 1’	‘ 1’	‘ 1’	‘ 1 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘ 1’	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	‘ 3 ’	‘ 3 ’	‘ 3 ’	‘ 3 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘ 3 ’	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	‘1’	‘1’	‘1’	‘1 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘1’	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	‘0’	‘0’	‘0’	‘0 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0’	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	‘-1’	‘-1’	‘-1’	‘-1 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘-1’	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	‘42’	‘42’	‘42’	‘42 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘42’	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	‘1.3’	‘1.3’	‘1.3’	‘1.3 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘1.3’	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	‘0.0’	‘0.0’	‘0.0’	‘0.0 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0.0’	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	‘-1.305’	‘-1.305’	‘-1.305’	‘-1.305 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘-1.305’	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	‘true’	‘true’	‘true’	‘true ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘true’	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	‘false’	‘false’	‘false’	‘false ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘false’	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	‘null’	‘null’	‘null’	‘null ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘null’	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	‘123str’	‘123str’	‘123str’	‘123str ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘123str’	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	‘str123’	‘str123’	‘str123’	‘str123 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘str123’	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	‘123, "str"’	‘123, "str"’	‘123, "str"’	‘123, "str" ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘123, "str"’	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	‘0xCC00F9’	‘0xCC00F9’	‘0xCC00F9’	‘0xCC00F9 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0xCC00F9’	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	‘0123’	‘0123’	‘0123’	‘0123 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘0123’	$x = *string[4]* : ‘0123’
$x = array()	‘Array’ ( #2 )	‘Array’	‘Array’	‘Array ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	‘Array’ ( #2 )	‘Array’	‘Array’	‘Array ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [1] => ‘string’ )	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	‘Array’ ( #2 )	‘Array’	‘Array’	‘Array ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	Array: ( [0] => null [1] => ‘1’ [2] => ‘1.3’ [3] => ‘123str’ [4] => ‘str123’ [5] => null )	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	‘Object’ ( #3 )	‘Object id #11’	‘Object id #11’	‘Object id #11 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	‘Object’ ( #3 )	‘Object id #16’	‘Object id #16’	‘Object id #16 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	‘Object id #16’	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #247 ( = RESOURCE )	‘Resource id #247’	‘Resource id #247’	‘Resource id #247’	‘Resource id #247 ’	E: not available (PHP 5.2.0+)	E: not available (PHP 5.2.0+)	null	$x = *resource* : Resource id #247 ( = RESOURCE )

Notice: Undefined index: notset
Notice: Array to string conversion
Notice: Object of class stdClass/TestObject/TestObjectToString to string conversion

^{‡ 1}

Depending on your error handling settings/exception catching and your PHP version, using settype( $copy, 'string' ) on an object which does not have a __toString() method will result either in the string Object or will return a (catchable) fatal error.

^{‡ 2}

Before PHP < 5.2.0, the __toString() method was only available to echo/print statements, so casting to string would still result in Object, even when the object contained a __toString() method.

^{‡ 3}

The code snippet is simplified for brevity. Please refer to the source of this file on GitHub for full details on how to use filter_var_array().

^{‡ 4}

Uses an external library

String tests	is_string()	empty()	== ''	=== ''	ctype_alpha() ^‡1	preg_match (`^[A-Za-z]+$`)	preg_match (`^\p{L}+$`u)	ctype_alnum() ^‡1	preg_match (`^[A-Za-z0-9]+$`)	preg_match (`^\w+$`)	preg_match (`^\w+$`u) ^‡2	preg_match (`^[\p{L}\p{N}]+$`u)	strlen()	count_chars (…)	mb_strlen()	$x{2}	trim()	String tests
String tests	is_string()	empty()	== ''	=== ''	ctype_alpha() ^‡1	preg_match (`^[A-Za-z]+$`)	preg_match (`^\p{L}+$`u)	ctype_alnum() ^‡1	preg_match (`^[A-Za-z0-9]+$`)	preg_match (`^\w+$`)	preg_match (`^\w+$`u) ^‡2	preg_match (`^[\p{L}\p{N}]+$`u)	strlen()	count_chars (…)	mb_strlen()	$x{2}	trim()	String tests
$x = *null* : ( = NULL )	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	0	0	0	null	‘’	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	0	0	0	null	‘’	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	0	0	0	null	‘’	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	1	1	1	null	‘1’	$x = *bool* : 1 ( = true )
$x = *int* : 1	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	1	1	1	null	‘1’	$x = *int* : 1
$x = *int* : 0	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	1	1	1	null	‘0’	$x = *int* : 0
$x = *int* : -1	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	2	2	2	null	‘-1’	$x = *int* : -1
$x = *int* : 42	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	2	2	2	null	‘42’	$x = *int* : 42
^†i8$x = *int* : 13369593	false	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	8	8	8	null	‘13369593’	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	2	2	2	null	‘42’	^†i9$x = *int* : 42
$x = *float* : 1.3	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	3	3	3	null	‘1.3’	$x = *float* : 1.3
$x = *float* : 0.005	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	5	5	5	null	‘0.005’	$x = *float* : 0.005
$x = *float* : 0	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	1	1	1	null	‘0’	$x = *float* : 0
$x = *float* : -1.3	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	4	4	4	null	‘-1.3’	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	7	7	7	null	‘-1.#IND’	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	false	true	true	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	1	1	1	null	‘0’	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	7	7	7	null	‘-1.#INF’	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	false	false	false	false	false	false	E: not available (PHP 5.1+)	false	true	true	true	E: not available (PHP 5.1+)	9	9	9	null	‘123450000’	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	true	true	true	true	true	false	E: not available (PHP 5.1+)	true	false	false	false	E: not available (PHP 5.1+)	0	0	0	‘’ ( #2 )	‘’	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	1	1	1	‘’ ( #2 )	‘’	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	2	2	2	‘’ ( #2 )	‘1’	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	3	3	3	‘ ’	‘3’	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	true	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	1	1	1	‘’ ( #2 )	‘1’	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	true	true	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	1	1	1	‘’ ( #2 )	‘0’	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	2	2	2	‘’ ( #2 )	‘-1’	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	true	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	2	2	2	‘’ ( #2 )	‘42’	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	3	3	3	‘3’	‘1.3’	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	3	3	3	‘0’	‘0.0’	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	6	6	6	‘.’	‘-1.305’	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	true	false	false	false	true	true	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	4	4	4	‘u’	‘true’	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	true	false	false	false	true	true	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	5	5	5	‘l’	‘false’	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	true	false	false	false	true	true	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	4	4	4	‘l’	‘null’	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	true	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	6	6	6	‘3’	‘123str’	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	true	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	6	6	6	‘r’	‘str123’	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	10	10	10	‘3’	‘123, "str"’	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	true	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	8	8	8	‘C’	‘0xCC00F9’	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	true	false	false	false	false	false	E: not available (PHP 5.1+)	true	true	true	true	E: not available (PHP 5.1+)	4	4	4	‘2’	‘0123’	$x = *string[4]* : ‘0123’
$x = *string[27]* : ‘Iñtërnâtiônàlizætiøn’	true	false	false	false	false	false	E: not available (PHP 5.1+)	false	false	false	false	E: not available (PHP 5.1+)	27	27	20	‘±’	‘Iñtërnâtiônàlizætiøn’	$x = *string[27]* : ‘Iñtërnâtiônàlizætiøn’
$x = array()	false	true	false	false	false	Error ( #3 )	E: not available (PHP 5.1+)	false	Error ( #3 )	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	5 ( #4 )	5 ( #4 )	false ( #5 )	null ( #6 )	‘Array’ ( #4 )	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	false	false	false	false	false	Error ( #3 )	E: not available (PHP 5.1+)	false	Error ( #3 )	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	5 ( #4 )	5 ( #4 )	false ( #5 )	null ( #6 )	‘Array’ ( #4 )	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	false	false	false	false	false	Error ( #3 )	E: not available (PHP 5.1+)	false	Error ( #3 )	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	5 ( #4 )	5 ( #4 )	false ( #5 )	1.3	‘Array’ ( #4 )	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	false	false	false	false	false	Error ( #3 )	E: not available (PHP 5.1+)	false	Error ( #3 )	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	6 ( #7 )	6 ( #7 )	false ( #5 )	Fatal error ( #8 )	‘Object’ ( #7 )	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	false	false	false	false	false	Error ( #3 )	E: not available (PHP 5.1+)	false	Error ( #3 )	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	6 ( #7 )	6 ( #7 )	false ( #5 )	Fatal error ( #8 )	‘Object’ ( #7 )	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #293 ( = RESOURCE )	false	false	false	false	false	Error ( #3 )	E: not available (PHP 5.1+)	false	Error ( #3 )	Error ( #3 )	Error ( #3 )	E: not available (PHP 5.1+)	16	16	false ( #5 )	null	‘Resource id #293’	$x = *resource* : Resource id #293 ( = RESOURCE )

Notice: Undefined index: notset
Notice: Uninitialized string offset: 2
Warning: preg_match() expects parameter 2 to be string, array/object/resource given
Notice: Array to string conversion
Warning: mb_strlen() expects parameter 1 to be string, array/object/resource given
Notice: Undefined offset: 2
Notice: Object of class stdClass/TestObject/TestObjectToString to string conversion
Fatal error: Cannot use object of type stdClass/TestObject/TestObjectToString as array

^{‡ 1}

^{‡ 2}

What \w matches is locale dependent. The locale for these cheatsheets are set to C. Results with other locales will vary.

Array casting	settype ( $copy, 'array' )	(array)	CastToType::_array ( $x, false ) ^‡1	Array casting
Array casting	settype ( $copy, 'array' )	(array)	CastToType::_array ( $x, false ) ^‡1	Array casting
$x = *null* : ( = NULL )	array()	array()	null	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	array()	array()	null	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	Array: ( [0] => b false )	Array: ( [0] => b false )	Array: ( [0] => b false )	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	Array: ( [0] => b true )	Array: ( [0] => b true )	Array: ( [0] => b true )	$x = *bool* : 1 ( = true )
$x = *int* : 1	Array: ( [0] => 1 )	Array: ( [0] => 1 )	Array: ( [0] => 1 )	$x = *int* : 1
$x = *int* : 0	Array: ( [0] => 0 )	Array: ( [0] => 0 )	Array: ( [0] => 0 )	$x = *int* : 0
$x = *int* : -1	Array: ( [0] => -1 )	Array: ( [0] => -1 )	Array: ( [0] => -1 )	$x = *int* : -1
$x = *int* : 42	Array: ( [0] => 42 )	Array: ( [0] => 42 )	Array: ( [0] => 42 )	$x = *int* : 42
^†i8$x = *int* : 13369593	Array: ( [0] => 13369593 )	Array: ( [0] => 13369593 )	Array: ( [0] => 13369593 )	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	Array: ( [0] => 42 )	Array: ( [0] => 42 )	Array: ( [0] => 42 )	^†i9$x = *int* : 42
$x = *float* : 1.3	Array: ( [0] => 1.3 )	Array: ( [0] => 1.3 )	Array: ( [0] => 1.3 )	$x = *float* : 1.3
$x = *float* : 0.005	Array: ( [0] => 0.005 )	Array: ( [0] => 0.005 )	Array: ( [0] => 0.005 )	$x = *float* : 0.005
$x = *float* : 0	Array: ( [0] => 0 )	Array: ( [0] => 0 )	Array: ( [0] => 0 )	$x = *float* : 0
$x = *float* : -1.3	Array: ( [0] => -1.3 )	Array: ( [0] => -1.3 )	Array: ( [0] => -1.3 )	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	Array: ( [0] => -1.#IND )	Array: ( [0] => -1.#IND )	Array: ( [0] => -1.#IND )	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	Array: ( [0] => 0 )	Array: ( [0] => 0 )	Array: ( [0] => 0 )	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	Array: ( [0] => -1.#INF )	Array: ( [0] => -1.#INF )	Array: ( [0] => -1.#INF )	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	Array: ( [0] => 123450000 )	Array: ( [0] => 123450000 )	Array: ( [0] => 123450000 )	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	Array: ( [0] => ‘’ )	Array: ( [0] => ‘’ )	Array: ( [0] => ‘’ )	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	Array: ( [0] => ‘ ’ )	Array: ( [0] => ‘ ’ )	Array: ( [0] => ‘ ’ )	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	Array: ( [0] => ‘ 1’ )	Array: ( [0] => ‘ 1’ )	Array: ( [0] => ‘ 1’ )	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	Array: ( [0] => ‘ 3 ’ )	Array: ( [0] => ‘ 3 ’ )	Array: ( [0] => ‘ 3 ’ )	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	Array: ( [0] => ‘1’ )	Array: ( [0] => ‘1’ )	Array: ( [0] => ‘1’ )	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	Array: ( [0] => ‘0’ )	Array: ( [0] => ‘0’ )	Array: ( [0] => ‘0’ )	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	Array: ( [0] => ‘-1’ )	Array: ( [0] => ‘-1’ )	Array: ( [0] => ‘-1’ )	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	Array: ( [0] => ‘42’ )	Array: ( [0] => ‘42’ )	Array: ( [0] => ‘42’ )	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	Array: ( [0] => ‘1.3’ )	Array: ( [0] => ‘1.3’ )	Array: ( [0] => ‘1.3’ )	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	Array: ( [0] => ‘0.0’ )	Array: ( [0] => ‘0.0’ )	Array: ( [0] => ‘0.0’ )	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	Array: ( [0] => ‘-1.305’ )	Array: ( [0] => ‘-1.305’ )	Array: ( [0] => ‘-1.305’ )	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	Array: ( [0] => ‘true’ )	Array: ( [0] => ‘true’ )	Array: ( [0] => ‘true’ )	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	Array: ( [0] => ‘false’ )	Array: ( [0] => ‘false’ )	Array: ( [0] => ‘false’ )	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	Array: ( [0] => ‘null’ )	Array: ( [0] => ‘null’ )	Array: ( [0] => ‘null’ )	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	Array: ( [0] => ‘123str’ )	Array: ( [0] => ‘123str’ )	Array: ( [0] => ‘123str’ )	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	Array: ( [0] => ‘str123’ )	Array: ( [0] => ‘str123’ )	Array: ( [0] => ‘str123’ )	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	Array: ( [0] => ‘123, "str"’ )	Array: ( [0] => ‘123, "str"’ )	Array: ( [0] => ‘123, "str"’ )	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	Array: ( [0] => ‘0xCC00F9’ )	Array: ( [0] => ‘0xCC00F9’ )	Array: ( [0] => ‘0xCC00F9’ )	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	Array: ( [0] => ‘0123’ )	Array: ( [0] => ‘0123’ )	Array: ( [0] => ‘0123’ )	$x = *string[4]* : ‘0123’
$x = array()	array()	array()	null	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	Array: ( [1] => ‘string’ )	Array: ( [1] => ‘string’ )	Array: ( [1] => ‘string’ )	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	array()	array()	null	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	Array: ( [test3] => ‘some string’ [test1] => null [test2] => b true )	Array: ( [test3] => ‘some string’ [test1] => null [test2] => b true )	Array: ( [test3] => ‘some string’ [test1] => null [test2] => b true )	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #296 ( = RESOURCE )	Array: ( [0] => Resource id #296 )	Array: ( [0] => Resource id #296 )	Array: ( [0] => Resource id #296 )	$x = *resource* : Resource id #296 ( = RESOURCE )

Notice: Undefined index: notset

^{‡ 1}

Uses an external library

Array testing	is_array()	count()	empty()	count() > 0	isset ( $x[0] ) ^‡1	array_key_exists ( 0, $x ) ^‡1	isset ( $x['foo'] ) ^‡1	key()	current()	$x['foo']	$x['foo']['bar']	array_filter()	Array testing
Array testing	is_array()	count()	empty()	count() > 0	isset ( $x[0] ) ^‡1	array_key_exists ( 0, $x ) ^‡1	isset ( $x['foo'] ) ^‡1	key()	current()	$x['foo']	$x['foo']['bar']	array_filter()	Array testing
$x = *null* : ( = NULL )	false	0	true	false	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	false	0	true	false	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	false	1	true	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *bool* : 1 ( = true )
$x = *int* : 1	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *int* : 1
$x = *int* : 0	false	1	true	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *int* : 0
$x = *int* : -1	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *int* : -1
$x = *int* : 42	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *int* : 42
^†i8$x = *int* : 13369593	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	^†i9$x = *int* : 42
$x = *float* : 1.3	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *float* : 1.3
$x = *float* : 0.005	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *float* : 0.005
$x = *float* : 0	false	1	true	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *float* : 0
$x = *float* : -1.3	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	false	1	true	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	false	1	true	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	false	1	true	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	‘’ ( #6 )	Fatal error ( #7 )	null ( #5 )	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘ ’	Fatal error ( #7 )	null ( #5 )	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘ ’	Fatal error ( #7 )	null ( #5 )	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘ ’	Fatal error ( #7 )	null ( #5 )	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘1’	Fatal error ( #7 )	null ( #5 )	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	false	1	true	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘0’	Fatal error ( #7 )	null ( #5 )	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘-’	Fatal error ( #7 )	null ( #5 )	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘4’	Fatal error ( #7 )	null ( #5 )	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘1’	Fatal error ( #7 )	null ( #5 )	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘0’	Fatal error ( #7 )	null ( #5 )	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘-’	Fatal error ( #7 )	null ( #5 )	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘t’	Fatal error ( #7 )	null ( #5 )	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘f’	Fatal error ( #7 )	null ( #5 )	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘n’	Fatal error ( #7 )	null ( #5 )	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘1’	Fatal error ( #7 )	null ( #5 )	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘s’	Fatal error ( #7 )	null ( #5 )	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘1’	Fatal error ( #7 )	null ( #5 )	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘0’	Fatal error ( #7 )	null ( #5 )	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	false	1	false	true	true	false ( #2 ) ( #2 )	true	b false ( #3 )	b false ( #4 )	‘0’	Fatal error ( #7 )	null ( #5 )	$x = *string[4]* : ‘0123’
$x = array()	true	0	true	false	false	false	false	null	b false	null ( #8 )	null ( #8 )	array()	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	true	1	false	true	false	false	false	1	‘string’	null ( #8 )	null ( #8 )	Array: ( [1] => ‘string’ )	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	true	6	false	true	true	true	false	0	b false	null ( #8 )	null ( #8 )	Array: ( [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ )	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	false	1	false	true	Fatal error ( #9 )	false	Fatal error ( #9 )	null	b false	Fatal error ( #9 )	Fatal error ( #9 )	null ( #5 )	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObject ( property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method*: print_it ) )	false	1	false	true	Fatal error ( #9 )	false	Fatal error ( #9 )	‘test1’	null	Fatal error ( #9 )	Fatal error ( #9 )	null ( #5 )	$x = Object: ( *Class: TestObject ( property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method*: print_it ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	false	1	false	true	Fatal error ( #9 )	false	Fatal error ( #9 )	‘test3’	‘some string’	Fatal error ( #9 )	Fatal error ( #9 )	null ( #5 )	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #342 ( = RESOURCE )	false	1	false	true	false	false ( #2 ) ( #2 )	false	b false ( #3 )	b false ( #4 )	null	null	null ( #5 )	$x = *resource* : Resource id #342 ( = RESOURCE )

Notice: Undefined index: notset
Warning: array_key_exists() [function.array-key-exists]: The second argument should be either an array or an object
Warning: key() [function.key]: Passed variable is not an array or object
Warning: current() [function.current]: Passed variable is not an array or object
Warning: array_filter() [function.array-filter]: The first argument should be an array
Notice: Uninitialized string offset: 0
Fatal error: Cannot use string offset as an array
Notice: Undefined index: foo
Fatal error: Cannot use object of type stdClass/TestObject/TestObjectToString as array

^{‡ 1}

Whether to use isset() or array_key_exists() depends on what you want to know:

isset( $array[$key] ) will tell you whether the array key exists and has been assigned a value.
Used on its own it will give undesired results when used on strings as characters within a string can be approached using the $x[] syntax as well.
Also, it will cause fatal errors when used on objects.
array_key_exists( $key, $array ) will tell you only whether the array key exists, but will not check whether it has a value assigned to it.
Used on its own, it will show a warning if $array is not an array

This said, we can conclude that to avoid warnings and undesired results you will always have to use an is_array() first.
Also note that isset() is faster than array_key_exists(), but as said above, will return false if no value has been assigned.

Objects	settype ( $copy, 'object' )	(object)	CastToType::_object ( $x, false ) ^‡1	is_object()	is_a ( $x, 'TestObject' )	instanceof TestObject	get_class()	get_parent_class()	is_subclass_of ( $x, 'TestObject' )	Objects
Objects	settype ( $copy, 'object' )	(object)	CastToType::_object ( $x, false ) ^‡1	is_object()	is_a ( $x, 'TestObject' )	instanceof TestObject	get_class()	get_parent_class()	is_subclass_of ( $x, 'TestObject' )	Objects
$x = *null* : ( = NULL )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	null	false	false	false	false	false	false	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	null	false	false	false	false	false	false	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	Object: ( *Class: stdClass ( property: scalar = b false* ) )	Object: ( *Class: stdClass ( property: scalar = b false* ) )	Object: ( *Class: stdClass ( property: scalar = b false* ) )	false	false	false	false	false	false	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	Object: ( *Class: stdClass ( property: scalar = b true* ) )	Object: ( *Class: stdClass ( property: scalar = b true* ) )	Object: ( *Class: stdClass ( property: scalar = b true* ) )	false	false	false	false	false	false	$x = *bool* : 1 ( = true )
$x = *int* : 1	Object: ( *Class: stdClass ( property*: scalar = 1 ) )	Object: ( *Class: stdClass ( property*: scalar = 1 ) )	Object: ( *Class: stdClass ( property*: scalar = 1 ) )	false	false	false	false	false	false	$x = *int* : 1
$x = *int* : 0	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	false	false	false	false	false	false	$x = *int* : 0
$x = *int* : -1	Object: ( *Class: stdClass ( property*: scalar = -1 ) )	Object: ( *Class: stdClass ( property*: scalar = -1 ) )	Object: ( *Class: stdClass ( property*: scalar = -1 ) )	false	false	false	false	false	false	$x = *int* : -1
$x = *int* : 42	Object: ( *Class: stdClass ( property*: scalar = 42 ) )	Object: ( *Class: stdClass ( property*: scalar = 42 ) )	Object: ( *Class: stdClass ( property*: scalar = 42 ) )	false	false	false	false	false	false	$x = *int* : 42
^†i8$x = *int* : 13369593	Object: ( *Class: stdClass ( property*: scalar = 13369593 ) )	Object: ( *Class: stdClass ( property*: scalar = 13369593 ) )	Object: ( *Class: stdClass ( property*: scalar = 13369593 ) )	false	false	false	false	false	false	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	Object: ( *Class: stdClass ( property*: scalar = 42 ) )	Object: ( *Class: stdClass ( property*: scalar = 42 ) )	Object: ( *Class: stdClass ( property*: scalar = 42 ) )	false	false	false	false	false	false	^†i9$x = *int* : 42
$x = *float* : 1.3	Object: ( *Class: stdClass ( property*: scalar = 1.3 ) )	Object: ( *Class: stdClass ( property*: scalar = 1.3 ) )	Object: ( *Class: stdClass ( property*: scalar = 1.3 ) )	false	false	false	false	false	false	$x = *float* : 1.3
$x = *float* : 0.005	Object: ( *Class: stdClass ( property*: scalar = 0.005 ) )	Object: ( *Class: stdClass ( property*: scalar = 0.005 ) )	Object: ( *Class: stdClass ( property*: scalar = 0.005 ) )	false	false	false	false	false	false	$x = *float* : 0.005
$x = *float* : 0	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	false	false	false	false	false	false	$x = *float* : 0
$x = *float* : -1.3	Object: ( *Class: stdClass ( property*: scalar = -1.3 ) )	Object: ( *Class: stdClass ( property*: scalar = -1.3 ) )	Object: ( *Class: stdClass ( property*: scalar = -1.3 ) )	false	false	false	false	false	false	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	Object: ( *Class: stdClass ( property*: scalar = -1.#IND ) )	Object: ( *Class: stdClass ( property*: scalar = -1.#IND ) )	Object: ( *Class: stdClass ( property*: scalar = -1.#IND ) )	false	false	false	false	false	false	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	Object: ( *Class: stdClass ( property*: scalar = 0 ) )	false	false	false	false	false	false	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	Object: ( *Class: stdClass ( property*: scalar = -1.#INF ) )	Object: ( *Class: stdClass ( property*: scalar = -1.#INF ) )	Object: ( *Class: stdClass ( property*: scalar = -1.#INF ) )	false	false	false	false	false	false	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	Object: ( *Class: stdClass ( property*: scalar = 123450000 ) )	Object: ( *Class: stdClass ( property*: scalar = 123450000 ) )	Object: ( *Class: stdClass ( property*: scalar = 123450000 ) )	false	false	false	false	false	false	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	Object: ( *Class: stdClass ( property*: scalar = ‘’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘’ ) )	null	false	false	false	false	false	false ( #2 )	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	Object: ( *Class: stdClass ( property*: scalar = ‘ ’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘ ’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘ ’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	Object: ( *Class: stdClass ( property*: scalar = ‘ 1’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘ 1’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘ 1’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	Object: ( *Class: stdClass ( property*: scalar = ‘ 3 ’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘ 3 ’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘ 3 ’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	Object: ( *Class: stdClass ( property*: scalar = ‘1’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘1’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘1’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	Object: ( *Class: stdClass ( property*: scalar = ‘0’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	Object: ( *Class: stdClass ( property*: scalar = ‘-1’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘-1’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘-1’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	Object: ( *Class: stdClass ( property*: scalar = ‘42’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘42’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘42’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	Object: ( *Class: stdClass ( property*: scalar = ‘1.3’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘1.3’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘1.3’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	Object: ( *Class: stdClass ( property*: scalar = ‘0.0’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0.0’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0.0’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	Object: ( *Class: stdClass ( property*: scalar = ‘-1.305’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘-1.305’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘-1.305’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	Object: ( *Class: stdClass ( property*: scalar = ‘true’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘true’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘true’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	Object: ( *Class: stdClass ( property*: scalar = ‘false’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘false’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘false’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	Object: ( *Class: stdClass ( property*: scalar = ‘null’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘null’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘null’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	Object: ( *Class: stdClass ( property*: scalar = ‘123str’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘123str’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘123str’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	Object: ( *Class: stdClass ( property*: scalar = ‘str123’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘str123’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘str123’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	Object: ( *Class: stdClass ( property*: scalar = ‘123, "str"’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘123, "str"’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘123, "str"’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	Object: ( *Class: stdClass ( property*: scalar = ‘0xCC00F9’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0xCC00F9’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0xCC00F9’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	Object: ( *Class: stdClass ( property*: scalar = ‘0123’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0123’ ) )	Object: ( *Class: stdClass ( property*: scalar = ‘0123’ ) )	false	false	false	false	false	false ( #2 )	$x = *string[4]* : ‘0123’
$x = array()	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	null	false	false	false	false	false	false	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class: stdClass ( property*: 1 = ‘string’ ) )	false	false	false	false	false	false	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class: stdClass ( property: 0 = b false* *property: 1 = 1 property: 2 = 1.3 property: 3 = ‘123str’ property: 4 = ‘str123’ property*: 5 = null ) )	false	false	false	false	false	false	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Array: ( [s *(string)] => string[6]* : ‘simple’ [m *(string)] => Array: ( [0 (int)] => string[5]* : ‘test1’ [1 *(int)] => string[5]* : ‘test2’ ) )	Object: ( *Class: stdClass ( property: s = ‘simple’ property*: m (array) Array: ( [0] => ‘test1’ [1] => ‘test2’ ) ) )	Object: ( *Class: stdClass ( property: s = ‘simple’ property*: m (array) Array: ( [0] => ‘test1’ [1] => ‘test2’ ) ) )	Object: ( *Class: stdClass ( property: s = ‘simple’ property*: m (array) Array: ( [0] => ‘test1’ [1] => ‘test2’ ) ) )	false	false	false	false	false	false	$x = Array: ( [s *(string)] => string[6]* : ‘simple’ [m *(string)] => Array: ( [0 (int)] => string[5]* : ‘test1’ [1 *(int)] => string[5]* : ‘test2’ ) )
$x = Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	null	true	false	false	‘stdClass’	false	false	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObject ( property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method*: print_it ) )	Object: ( *Class: TestObject ( property: test1 = null property: test2 = b true* *method*: print_it ) )	Object: ( *Class: TestObject ( property: test1 = null property: test2 = b true* *method*: print_it ) )	Object: ( *Class: TestObject ( property: test1 = null property: test2 = b true* *method*: print_it ) )	true	true	true	‘TestObject’	false	false	$x = Object: ( *Class: TestObject ( property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method*: print_it ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	true	true	true	‘TestObjectToString’	‘TestObject’	true	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #345 ( = RESOURCE )	Object: ( *Class: stdClass ( property*: scalar = Resource id #345 ) )	Object: ( *Class: stdClass ( property*: scalar = Resource id #345 ) )	Object: ( *Class: stdClass ( property*: scalar = Resource id #345 ) )	false	false	false	false	false	false	$x = *resource* : Resource id #345 ( = RESOURCE )

Notice: Undefined index: notset
Warning: Unknown class passed as parameter

^{‡ 1}

Uses an external library

Resources	is_resource()	get_resource_type()	Resources
Resources	is_resource()	get_resource_type()	Resources
$x = *null* : ( = NULL )	false	false ( #2 )	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	false	false ( #2 )	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	false	false ( #2 )	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	false	false ( #2 )	$x = *bool* : 1 ( = true )
$x = *int* : 1	false	false ( #2 )	$x = *int* : 1
$x = *int* : 0	false	false ( #2 )	$x = *int* : 0
$x = *int* : -1	false	false ( #2 )	$x = *int* : -1
$x = *int* : 42	false	false ( #2 )	$x = *int* : 42
^†i8$x = *int* : 13369593	false	false ( #2 )	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	false	false ( #2 )	^†i9$x = *int* : 42
$x = *float* : 1.3	false	false ( #2 )	$x = *float* : 1.3
$x = *float* : 0.005	false	false ( #2 )	$x = *float* : 0.005
$x = *float* : 0	false	false ( #2 )	$x = *float* : 0
$x = *float* : -1.3	false	false ( #2 )	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	false	false ( #2 )	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	false	false ( #2 )	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	false	false ( #2 )	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	false	false ( #2 )	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	false	false ( #2 )	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	false	false ( #2 )	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	false	false ( #2 )	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	false	false ( #2 )	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	false	false ( #2 )	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	false	false ( #2 )	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	false	false ( #2 )	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	false	false ( #2 )	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	false	false ( #2 )	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	false	false ( #2 )	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	false	false ( #2 )	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	false	false ( #2 )	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	false	false ( #2 )	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	false	false ( #2 )	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	false	false ( #2 )	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	false	false ( #2 )	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	false	false ( #2 )	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	false	false ( #2 )	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	false	false ( #2 )	$x = *string[4]* : ‘0123’
$x = array()	false	false ( #2 )	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	false	false ( #2 )	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	false	false ( #2 )	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	false	false ( #2 )	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	false	false ( #2 )	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #393 ( = RESOURCE )	true	‘stream’	$x = *resource* : Resource id #393 ( = RESOURCE )
$x = *resource* : Resource id #394 ( = RESOURCE )	true	‘gd’	$x = *resource* : Resource id #394 ( = RESOURCE )

Notice: Undefined index: notset
Warning: Supplied argument is not a valid resource handle

Basic Arithmetic	$x = ++$x ^‡1	$x = $x++ ^‡1	$x = --$x ^‡1	$x = $x-- ^‡1	-$x	$x + 0	$x - 0	$x * 1	$x / 1	$x % 1	Basic Arithmetic
Basic Arithmetic	$x = ++$x ^‡1	$x = $x++ ^‡1	$x = --$x ^‡1	$x = $x-- ^‡1	-$x	$x + 0	$x - 0	$x * 1	$x / 1	$x % 1	Basic Arithmetic
$x = *null* : ( = NULL )	1	null	null	null	0	0	0	0	0	0	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	1	null	null	null	0	0	0	0	0	0	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	b false	b false	b false	b false	0	0	0	0	0	0	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	b true	b true	b true	b true	-1	1	1	1	1	0	$x = *bool* : 1 ( = true )
$x = *int* : 1	2	1	0	1	-1	1	1	1	1	0	$x = *int* : 1
$x = *int* : 0	1	0	-1	0	0	0	0	0	0	0	$x = *int* : 0
$x = *int* : -1	0	-1	-2	-1	1	-1	-1	-1	-1	0	$x = *int* : -1
$x = *int* : 42	43	42	41	42	-42	42	42	42	42	0	$x = *int* : 42
^†i8$x = *int* : 13369593	13369594	13369593	13369592	13369593	-13369593	13369593	13369593	13369593	13369593	0	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	43	42	41	42	-42	42	42	42	42	0	^†i9$x = *int* : 42
$x = *float* : 1.3	2.3	1.3	0.3	1.3	-1.3	1.3	1.3	1.3	1.3	0	$x = *float* : 1.3
$x = *float* : 0.005	1.005	0.005	-0.995	0.005	-0.005	0.005	0.005	0.005	0.005	0	$x = *float* : 0.005
$x = *float* : 0	1	0	-1	0	0	0	0	0	0	0	$x = *float* : 0
$x = *float* : -1.3	-0.3	-1.3	-2.3	-1.3	1.3	-1.3	-1.3	-1.3	-1.3	0	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	-1.#IND	0	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	1	0	-1	0	0	0	0	0	0	0	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	-1.#INF	-1.#INF	-1.#INF	-1.#INF	1.#INF	-1.#INF	-1.#INF	-1.#INF	-1.#INF	0	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	123450001	123450000	123449999	123450000	-123450000	123450000	123450000	123450000	123450000	0	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	‘1’	‘’	-1	‘’	0	0	0	0	0	0	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	‘ ’	‘ ’	‘ ’	‘ ’	0	0	0	0	0	0	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	2	‘ 1’	0	‘ 1’	-1	1	1	1	1	0	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	‘ 3 ’	‘ 3 ’	‘ 3 ’	‘ 3 ’	-3	3	3	3	3	0	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	2	‘1’	0	‘1’	-1	1	1	1	1	0	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	1	‘0’	-1	‘0’	0	0	0	0	0	0	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	0	‘-1’	-2	‘-1’	1	-1	-1	-1	-1	0	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	43	‘42’	41	‘42’	-42	42	42	42	42	0	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	2.3	‘1.3’	0.3	‘1.3’	-1.3	1.3	1.3	1.3	1.3	0	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	1	‘0.0’	-1	‘0.0’	0	0	0	0	0	0	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	-0.305	‘-1.305’	-2.305	‘-1.305’	1.305	-1.305	-1.305	-1.305	-1.305	0	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	‘truf’	‘true’	‘true’	‘true’	0	0	0	0	0	0	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	‘falsf’	‘false’	‘false’	‘false’	0	0	0	0	0	0	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	‘nulm’	‘null’	‘null’	‘null’	0	0	0	0	0	0	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	‘123sts’	‘123str’	‘123str’	‘123str’	-123	123	123	123	123	0	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	‘str124’	‘str123’	‘str123’	‘str123’	0	0	0	0	0	0	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	‘123, "str"’	‘123, "str"’	‘123, "str"’	‘123, "str"’	-123	123	123	123	123	0	$x = *string[10]* : ‘123, "str"’
$x = *string[8]* : ‘0xCC00F9’	13369594	‘0xCC00F9’	13369592	‘0xCC00F9’	-13369593	13369593	13369593	13369593	13369593	0	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	124	‘0123’	122	‘0123’	-123	123	123	123	123	0	$x = *string[4]* : ‘0123’
$x = array()	array()	array()	array()	array()	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	0	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	Array: ( [1] => ‘string’ )	Array: ( [1] => ‘string’ )	Array: ( [1] => ‘string’ )	Array: ( [1] => ‘string’ )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	0	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	Array: ( [0] => b false [1] => 1 [2] => 1.3 [3] => ‘123str’ [4] => ‘str123’ [5] => null )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	0	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Object: ( *Class*: stdClass ( ) )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	0	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Object: ( *Class: TestObjectToString ( property: test3 = ‘some string’ property: test1 = null property: test2 = b true* *method: __toString method*: print_it ) )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	Fatal error ( #2 )	0	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #396 ( = RESOURCE )	Resource id #396	Resource id #396	Resource id #396	Resource id #396	-396	396	396	396	396	0	$x = *resource* : Resource id #396 ( = RESOURCE )

Notice: Undefined index: notset
Fatal error: Unsupported operand types

^{‡ 1}

Please take note: using the in-/decrementors on SplInt and SplFloat objects may give unexpected (inconsistent) results....

CType Extension	ctype_digit() ^‡1	ctype_xdigit() ^‡1	ctype_alpha() ^‡1	ctype_alnum() ^‡1	ctype_graph() ^‡1	ctype_print() ^‡1	ctype_upper() ^‡1	ctype_space() ^‡1	CType Extension
CType Extension	ctype_digit() ^‡1	ctype_xdigit() ^‡1	ctype_alpha() ^‡1	ctype_alnum() ^‡1	ctype_graph() ^‡1	ctype_print() ^‡1	ctype_upper() ^‡1	ctype_space() ^‡1	CType Extension
$x = *null* : ( = NULL )	false	false	false	false	false	false	false	false	$x = *null* : ( = NULL )
$x = *null* : ( = NULL )	false	false	false	false	false	false	false	false	$x = *null* : ( = NULL )
$x = *bool* : ( = false )	false	false	false	false	false	false	false	false	$x = *bool* : ( = false )
$x = *bool* : 1 ( = true )	false	false	false	false	false	false	false	false	$x = *bool* : 1 ( = true )
$x = *int* : 1	false	false	false	false	false	false	false	false	$x = *int* : 1
$x = *int* : 0	false	false	false	false	false	false	false	false	$x = *int* : 0
$x = *int* : -1	false	false	false	false	false	false	false	false	$x = *int* : -1
$x = *int* : 10	false	false	false	false	false	false	false	true	$x = *int* : 10
$x = *int* : 42	false	false	false	false	true	true	false	false	$x = *int* : 42
$x = *int* : 111	false	false	true	true	true	true	false	false	$x = *int* : 111
$x = *int* : 12345	true	true	false	true	true	‘’	‘’	‘’	$x = *int* : 12345
^†i8$x = *int* : 13369593	true	true	false	true	true	‘’	‘’	‘’	^†i8$x = *int* : 13369593
^†i9$x = *int* : 42	false	false	false	false	true	true	false	false	^†i9$x = *int* : 42
$x = *float* : 1.3	false	false	false	false	false	false	false	false	$x = *float* : 1.3
$x = *float* : 0.005	false	false	false	false	false	false	false	false	$x = *float* : 0.005
$x = *float* : 0	false	false	false	false	false	false	false	false	$x = *float* : 0
$x = *float* : -1.3	false	false	false	false	false	false	false	false	$x = *float* : -1.3
^†f5$x = *float* : -1.#IND	false	false	false	false	false	false	false	false	^†f5$x = *float* : -1.#IND
^†f6$x = *float* : 0	false	false	false	false	false	false	false	false	^†f6$x = *float* : 0
^†f7$x = *float* : -1.#INF	false	false	false	false	false	false	false	false	^†f7$x = *float* : -1.#INF
^†f9$x = *float* : 123450000	false	false	false	false	false	false	false	false	^†f9$x = *float* : 123450000
$x = *string[0]* : ‘’	true	true	true	true	true	true	true	true	$x = *string[0]* : ‘’
$x = *string[1]* : ‘ ’	false	false	false	false	false	true	false	true	$x = *string[1]* : ‘ ’
$x = *string[2]* : ‘ 1’	false	false	false	false	false	true	false	false	$x = *string[2]* : ‘ 1’
$x = *string[3]* : ‘ 3 ’	false	false	false	false	false	true	false	false	$x = *string[3]* : ‘ 3 ’
$x = *string[1]* : ‘1’	true	true	false	true	true	true	false	false	$x = *string[1]* : ‘1’
$x = *string[1]* : ‘0’	true	true	false	true	true	true	false	false	$x = *string[1]* : ‘0’
$x = *string[2]* : ‘-1’	false	false	false	false	true	true	false	false	$x = *string[2]* : ‘-1’
$x = *string[2]* : ‘42’	true	true	false	true	true	true	false	false	$x = *string[2]* : ‘42’
$x = *string[3]* : ‘1.3’	false	false	false	false	true	true	false	false	$x = *string[3]* : ‘1.3’
$x = *string[3]* : ‘0.0’	false	false	false	false	true	true	false	false	$x = *string[3]* : ‘0.0’
$x = *string[6]* : ‘-1.305’	false	false	false	false	true	true	false	false	$x = *string[6]* : ‘-1.305’
$x = *string[4]* : ‘true’	false	false	true	true	true	true	false	false	$x = *string[4]* : ‘true’
$x = *string[5]* : ‘false’	false	false	true	true	true	true	false	false	$x = *string[5]* : ‘false’
$x = *string[4]* : ‘null’	false	false	true	true	true	true	false	false	$x = *string[4]* : ‘null’
$x = *string[6]* : ‘123str’	false	false	false	true	true	true	false	false	$x = *string[6]* : ‘123str’
$x = *string[6]* : ‘str123’	false	false	false	true	true	true	false	false	$x = *string[6]* : ‘str123’
$x = *string[10]* : ‘123, "str"’	false	false	false	false	false	true	false	false	$x = *string[10]* : ‘123, "str"’
$x = *string[9]* : ‘123,"str"’	false	false	false	false	true	true	false	false	$x = *string[9]* : ‘123,"str"’
^†sk$x = *string[12]* : ‘123, "str" ’	false	false	false	false	false	false	false	false	^†sk$x = *string[12]* : ‘123, "str" ’
$x = *string[6]* : ‘AF036C’	false	true	false	true	true	true	false	false	$x = *string[6]* : ‘AF036C’
$x = *string[3]* : ‘FOO’	false	false	true	true	true	true	true	false	$x = *string[3]* : ‘FOO’
^†sn$x = *string[5]* : ‘\f ’	false	false	false	false	false	false	false	false	^†sn$x = *string[5]* : ‘\f ’
$x = *string[5]* : ‘*&$()’	false	false	false	false	true	true	false	false	$x = *string[5]* : ‘*&$()’
^†sp$x = *string[4]* : ‘ ’	false	false	false	false	false	false	false	false	^†sp$x = *string[4]* : ‘ ’
$x = *string[8]* : ‘0xCC00F9’	false	false	false	true	true	true	false	false	$x = *string[8]* : ‘0xCC00F9’
$x = *string[4]* : ‘0123’	true	true	false	true	true	true	false	false	$x = *string[4]* : ‘0123’
$x = *string[27]* : ‘Iñtërnâtiônàlizætiøn’	false	false	false	false	false	false	false	false	$x = *string[27]* : ‘Iñtërnâtiônàlizætiøn’
$x = array()	false	false	false	false	false	false	false	false	$x = array()
$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )	false	false	false	false	false	false	false	false	$x = Array: ( [1 *(int)] => string[6]* : ‘string’ )
$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )	false	false	false	false	false	false	false	false	$x = Array: ( [0 *(int)] => bool* : ( = false ) [1 *(int)] => int* : 1 [2 *(int)] => float* : 1.3 [3 *(int)] => string[6]* : ‘123str’ [4 *(int)] => string[6]* : ‘str123’ [5 *(int)] => null* : ( = NULL ) )
$x = Object: ( *Class*: stdClass ( ) )	false	false	false	false	false	false	false	false	$x = Object: ( *Class*: stdClass ( ) )
$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )	false	false	false	false	false	false	false	false	$x = Object: ( *Class: TestObjectToString ( property: test3 = string[11]* : ‘some string’ *property: test1 = null* : ( = NULL ) *property: test2 = bool* : 1 ( = true ) *method: __toString method*: print_it ) )
$x = *resource* : Resource id #399 ( = RESOURCE )	false	false	false	false	false	false	false	false	$x = *resource* : Resource id #399 ( = RESOURCE )

Notice: Undefined index: notset

^{‡ 1}

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