array ( 0 => 'index.php', 1 => 'PHP Manual', ), 'head' => array ( 0 => 'UTF-8', 1 => 'zh', ), 'this' => array ( 0 => 'arrayobject.uasort.php', 1 => 'ArrayObject::uasort', ), 'up' => array ( 0 => 'class.arrayobject.php', 1 => 'ArrayObject', ), 'prev' => array ( 0 => 'arrayobject.setiteratorclass.php', 1 => 'ArrayObject::setIteratorClass', ), 'next' => array ( 0 => 'arrayobject.uksort.php', 1 => 'ArrayObject::uksort', ), 'alternatives' => array ( ), 'source' => array ( 'lang' => 'en', 'path' => 'reference/spl/arrayobject/uasort.xml', ), ); $setup["toc"] = $TOC; $setup["toc_deprecated"] = $TOC_DEPRECATED; $setup["parents"] = $PARENTS; manual_setup($setup); ?>
(PHP 5 >= 5.2.0, PHP 7, PHP 8)
ArrayObject::uasort — Sort the entries with a user-defined comparison function and maintain key association
This function sorts the entries such that keys maintain their correlation with the entry that they are associated with, using a user-defined comparison function.
This is used mainly when sorting associative arrays where the actual element order is significant.
注意:
如果两个成员完全相同,那么它们将保持原来的顺序。 在 PHP 8.0.0 之前,它们在排序数组中的相对顺序是未定义的。
callback
在第一个参数小于,等于或大于第二个参数时,该比较函数必须相应地返回一个小于,等于或大于 0 的整数。
总是返回 true
。
示例 #1 ArrayObject::uasort() example
<?php
// Comparison function
function cmp($a, $b) {
if ($a == $b) {
return 0;
}
return ($a < $b) ? -1 : 1;
}
// Array to be sorted
$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);
$arrayObject = new ArrayObject($array);
print_r($arrayObject);
// Sort and print the resulting array
$arrayObject->uasort('cmp');
print_r($arrayObject);
?>
以上示例会输出:
Array ( [a] => 4 [b] => 8 [c] => -1 [d] => -9 [e] => 2 [f] => 5 [g] => 3 [h] => -4 ) Array ( [d] => -9 [h] => -4 [c] => -1 [e] => 2 [g] => 3 [a] => 4 [f] => 5 [b] => 8 )