The array_filter Function

The array_filter function filters an array using a given function. The function parameter will sequentially receive the array elements, and if the function returns true for an element, it remains in the array; if it returns false, it is removed. The array will contain only those elements for which the function returns true.

If the original array is associative, its keys are preserved.

Syntax

array_filter(array $array, ?callable $callback = null, int $mode = 0): array

Example

Let's keep only the positive elements in the array:

<?php
	function func($num)
	{
		if ($num >= 0) {
			return true;
		} else {
			return false;
		}
	}
	
	$arr = [1, -1, 2, -2, 3, -3];
	
	$res = array_filter($arr, 'func');
	var_dump($res);
?>

Code execution result:

[1, 2, 3]

Example

Let's shorten the condition:

<?php
	function func($num)
	{
		return $num >= 0;
	}
	
	$arr = [1, -1, 2, -2, 3, -3];
	
	$res = array_filter($arr, 'func');
	var_dump($res);
?>

Code execution result:

[1, 2, 3]

Example

Let's rewrite it using an anonymous function:

<?php
	$arr = [1, -1, 2, -2, 3, -3];
	
	$res = array_filter($arr, function($num) {
		return $num >= 0;
	});
	
	var_dump($res);
?>

Code execution result:

[1, 2, 3]

Example

Let's rewrite it using an arrow function:

<?php
	$arr = [1, -1, 2, -2, 3, -3];
	$res = array_filter($arr, fn($num) => $num >= 0);
	
	var_dump($res);
?>

Code execution result:

[1, 2, 3]

The array_filter Function

Syntax

Example

Example

Example

Example

See Also