(PHP 5 >= 5.2.0, PHP 7, PHP 8)
ArrayObject::uksort — Sort the entries by keys using a user-defined comparison function
This function sorts the keys of the entries using a user-supplied comparison function. The key to entry correlations will be maintained.
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.
callbackThe 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.
Returning non-integer values from the comparison
function, such as float, will result in an internal cast to
int of the callback's return value. So values such as
0.99 and 0.1 will both be cast to an
integer value of 0, which will compare such values as equal.
Always returns true.
| Version | Description |
|---|---|
| 8.2.0 |
The return type is true now; previously, it was bool.
|
Example #1 ArrayObject::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);
}
$array = array("John" => 1, "the Earth" => 2, "an apple" => 3, "a banana" => 4);
$arrayObject = new ArrayObject($array);
$arrayObject->uksort('cmp');
foreach ($arrayObject as $key => $value) {
echo "$key: $value\n";
}
?>
The above example will output:
an apple: 3 a banana: 4 the Earth: 2 John: 1