ArrayObject::uasort

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

ArrayObject::uasort — Sort the entries with a user-defined comparison function and maintain key association

说明

public ArrayObject::uasort(callable $callback): bool

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。

参数

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。

callback(mixed $a, mixed $b): int

返回值

总是返回 true 。

范例

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);
?>

以上例程会输出：

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
)

参见

ArrayObject::asort() - Sort the entries by value
ArrayObject::ksort() - Sort the entries by key
ArrayObject::natsort() - Sort entries using a "natural order" algorithm
ArrayObject::natcasesort() - Sort an array using a case insensitive "natural order" algorithm
ArrayObject::uksort() - Sort the entries by keys using a user-defined comparison function
uasort() - 使用用户自定义的比较函数，保持索引和值的对应关系，原地排序 array。

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User Contributed Notes 1 note

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poxetinho at gmail dot com ¶

10 years ago


Note that return values between (-1, 1) are being considered as 0.

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