ArrayObject::uasort

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

ArrayObject::uasortSort 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;
}

// 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