如何按值对多维数组进行排序? [英] How to Sort Multi-dimensional Array by Value?

问题描述

如何通过"order"键的值对该数组排序?即使这些值当前是连续的，也不一定总是如此.

How can I sort this array by the value of the "order" key? Even though the values are currently sequential, they will not always be.

Array
(
    [0] => Array
        (
            [hashtag] => a7e87329b5eab8578f4f1098a152d6f4
            [title] => Flower
            [order] => 3
        )

    [1] => Array
        (
            [hashtag] => b24ce0cd392a5b0b8dedc66c25213594
            [title] => Free
            [order] => 2
        )

    [2] => Array
        (
            [hashtag] => e7d31fc0602fb2ede144d18cdffd816b
            [title] => Ready
            [order] => 1
        )
)

推荐答案

尝试 usort ，如果您仍使用PHP 5.2或更早版本，则必须首先定义排序功能:

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

从PHP 5.3开始，您可以使用匿名函数:

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

最后，在PHP 7中，您可以使用太空飞船运算符:

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

要将其扩展到多维排序，如果第二个/第三个排序元素为零，请参考第二个/第三个排序元素-下文将详细说明.您还可以使用它对子元素进行排序.

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

如果需要保留键关联，请使用uasort()-请参见比较数组排序功能在手册中

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

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