PHP使用主&排序多维数组辅助键

问题描述：

如何通过主键和副键对多维数组排序? 例如，假设以下数组:

How do you sort a multidimensional array by primary and secondary key? For example, assuming the following array:

$result = array();

$result[0]["prio"] = 1;
$result[0]["date"] = '2010-02-28';
$result[0]["post"] = "February's thoughts";

$result[1]["prio"] = 0;
$result[1]["date"] = '2010-04-20';
$result[1]["post"] = "April's thoughts";

$result[2]["prio"] = 0;
$result[2]["date"] = '2010-05-30';
$result[2]["post"] = "May's thoughts";

我希望将列"prio"作为主键(升序)，将日期"列作为"主键(降序)"，以获得:>

I wish to sort the column 'prio' as the primary key (ascending) and 'date' as the secondary key (descending), to obtain:

$result[0]["prio"] = 0;
$result[0]["date"] = '2010-05-30';
$result[0]["post"] = "May's thoughts";
$result[1]["prio"] = 0;
$result[1]["date"] = '2010-04-20';
$result[1]["post"] = "April's thoughts";
$result[2]["prio"] = 1;
$result[2]["date"] = '2010-02-28';
$result[2]["post"] = "February's thoughts";

如何实现?

答

像这样使用usort:

Use usort like this:

$result = array();

$result[0]["prio"] = 1;
$result[0]["date"] = '2010-02-28';
$result[0]["post"] = "February's thoughts";

$result[1]["prio"] = 0;
$result[1]["date"] = '2010-04-20';
$result[1]["post"] = "April's thoughts";

$result[2]["prio"] = 0;
$result[2]["date"] = '2010-05-30';
$result[2]["post"] = "May's thoughts";

function fct($a ,$b) {

  if ($a['prio'] < $b['prio']) {
    return -1;
  } elseif  ($a['prio'] > $b['prio']) {
    return 1;
  } else {
    return strcmp($b['date'], $a['date']);
  }

}

usort($result, "fct");
print_r($result);

输出:

Array
(
    [0] => Array
        (
            [prio] => 0
            [date] => 2010-05-30
            [post] => May's thoughts
        )

    [1] => Array
        (
            [prio] => 0
            [date] => 2010-04-20
            [post] => April's thoughts
        )

    [2] => Array
        (
            [prio] => 1
            [date] => 2010-02-28
            [post] => February's thoughts
        )

)

PHP使用主&排序多维数组辅助键

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