The uasort Function

The uasort function sorts an array in ascending order by elements, preserving the keys of the associative array.

The uasort function sorts an array by element values, using a callback to determine the order of elements in the sorted array. The function modifies the array itself.

The comparison function must return an integer, which depending on the comparison result: less than, equal to, or greater than zero.

The function modifies the array itself.

Syntax

uasort(array &$array, int $flags = SORT_REGULAR): bool

Example

Let's sort the array in ascending order by elements:

<?php
	$arr = [
		'b' => 1,
		'e' => 3,
		'c' => 2,
		'a' => 5,
		'd' => 4,
	];
	
	function func($a, $b)
	{
		if ($a === $b) {
			return 0;
		} else if ($a < $b) {
			return -1;
		} else {
			return 1;
		}
	}
	
	uasort($arr, 'func');
	var_dump($arr);
?>

Code execution result:

[
	'b' => 1,
	'c' => 2,
	'e' => 3,
	'd' => 4,
	'a' => 5,
]

Example

Now let's sort the array by the number of characters in the array elements in ascending order:

<?php
	$arr = [
		'a' => '123',
		'b' => '1',
		'c' => '12345',
		'd' => '12',
		'e' => '1234',
	];
	
	function func($a, $b)
	{
		if (strlen($a) === strlen($b)) {
			return 0;
		} else if (strlen($a) < strlen($b)) {
			return -1;
		} else {
			return 1;
		}
	}
	
	uasort($arr, 'func');
	var_dump($arr);
?>

Code execution result:

[
	'b' => '1',
	'd' => '12',
	'a' => '123',
	'e' => '1234',
	'c' => '12345',
]

The uasort Function

Syntax

Example

Example

See Also