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Text lesson

array_filter()

Example

Filter an array’s values using a callback function.

<?php
function test_odd($var)
{
return($var & 1);
}

$a1=array(1,3,2,3,4);
print_r(array_filter($a1,“test_odd”));
?>

Definition and Usage

The array_filter() function filters an array’s values based on a callback function.

It passes each value of the input array to the callback function; if the callback returns true, the current value is included in the result array. Array keys are preserved.

Syntax

array_filter(array, callbackfunction, flag)

Parameter Values

Parameter	Description
array	Required. Specifies the array to be filtered.
callbackfunction	Optional. Defines the callback function to be used.
flag	Optional. Defines the arguments sent to the callback: ARRAY_FILTER_USE_KEY: Passes only the key as the argument to the callback (instead of the value). ARRAY_FILTER_USE_BOTH: Passes both the value and the key as arguments to the callback (instead of just the value).

Technical Details

Return Value:	Returns the array with filtered values.
PHP Version:	4.0.6+
PHP Changelog:	PHP 5.6 introduced an optional flag parameter.