PHP array_filter() Function

Example

Filter the values of an array 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 the values of an array using a callback function.

This function passes each value of the input array to the callback function. If the callback function returns true, the current value from input is returned into the result array. Array keys are preserved.

Syntax

array_filter(array, callbackfunction, flag)

Parameter Values

Parameter	Description
array	Required. Specifies the array to filter
callbackfunction	Optional. Specifies the callback function to use
flag	Optional. Specifies what arguments are sent to callback: ARRAY_FILTER_USE_KEY - pass key as the only argument to callback (instead of the value) ARRAY_FILTER_USE_BOTH - pass both value and key as arguments to callback (instead of the value)

Technical Details

Return Value:	Returns the filtered array
PHP Version:	4.0.6+
PHP Changelog:	PHP 5.6: Added optional flag parameter

❮ PHP Array Reference