php按自定义顺序对多维数组进行排序

Question

<分区>

Answer 1

采用按id对数组进行排序的标准代码:

usort($data, function($x, $y) { return $x['id'] - $y['id']; });

您要做的不是按 ID 本身排序，而是按每个 ID 的“权重”(表示您希望 ID 放入的任意顺序)。因此，创建一个数组，其中键是 id，值是权重，并使用它将 id 转换为权重:

// array_flip turns 0 => 112, 1 => 111, ... into 122 => 0, 111 => 1, ...
$weights = array_flip(array('112','111','132','100'));

usort($data, function($x, $y) use($weights) {
    return $weights[$x['id']] - $weights[$y['id']];
});

更新:由于您还想处理没有指定权重的 ID，因此您必须进一步扩展上述内容:

usort($data, function($x, $y) use($weights) {
    if (!isset($weights[$x['id']], $weights[$y['id']])) {
        // none of the ids have weight, so sort by bare id
        return $x['id'] - $y['id'];
    }
    else if (!isset($weights[$x['id']])) { 
        // x does not have weight, put it last
        return 1;
    }
    else if (!isset($weights[$y['id']])) {
        // y does not have weight, put it last
        return -1;
    }

    // both have weights, use them
    return $weights[$x['id']] - $weights[$y['id']];
});