uksort
(PHP 4, PHP 5, PHP 7, PHP 8)
uksort — Sort an array by keys using a user-defined comparison function
Description
Sorts array in place by keys using a
user-supplied comparison function to determine the order.
Note:
If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.
Note:
Resets array's internal pointer to the first element.
Parameters
-
array -
The input array.
-
callback -
The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.
Return Values
Always returns true.
Changelog
| Version | Description |
|---|---|
| 8.0.0 |
If callback expects a parameter to be passed
by reference, this function will now emit an E_WARNING.
|
Examples
Example #1 uksort() example
<?php
function cmp($a, $b)
{
$a = preg_replace('@^(a|an|the) @', '', $a);
$b = preg_replace('@^(a|an|the) @', '', $b);
return strcasecmp($a, $b);
}
$a = array("John" => 1, "the Earth" => 2, "an apple" => 3, "a banana" => 4);
uksort($a, "cmp");
foreach ($a as $key => $value) {
echo "$key: $value\n";
}
?>
The above example will output:
an apple: 3 a banana: 4 the Earth: 2 John: 1
See Also
- usort() - Sort an array by values using a user-defined comparison function
- uasort() - Sort an array with a user-defined comparison function and maintain index association
- The comparison of array sorting functions
