PHP 根据key 给二维数组分组
我们经常拿到一个二维数组出来，会发现结果和自己想要的有些偏差，可能需要根据二维数组里的某个字段对数组分组。 先来看以下数组，Array
(
[
0] => Array (
=> 1
=> 2
=> 1
=> 分组1
=> 2016-12-02 11:39:34 )
[
1] => Array (
=> 2
=> 31
=> 2
=> 分组1
=> 2016-12-12 11:39:50 )
[
2] => Array (
=> 3
=> 31
=> 4
=> 分组2
=> 2016-12-02 11:40:01 )
[
3] => Array (
=> 4
=> 2
=> 5
=> 分组2
=> 2016-12-07 10:21:40 )
[
4] => Array (
=> 5
=> 2
=> 3
=> 分组2
=> 2016-12-07 10:21:51 )
[
5] => Array (
=> 6
=> 2
=> 2
=> 分组3
=> 2016-12-07 10:21:56 )
[
6] => Array (
=> 7
=> 4
=> 2
=> 分组3
=> 2016-12-07 10:22:10 )
)
这里是一个很典型的例子，如果我希望把 数组中的数据 根据 type（分组） 分开处理，如果不分组，可能循环上会非常冗余，所以有了下面的一个分组函数：
public static function array_group_by($arr, $key) {
$grouped = [];foreach ($arr as $value) {$grouped[$value[$key]][] = $value; }
// Recursively build a nested grouping if more parameters are supplied // Each grouped array value is grouped according to the next sequential key
if (() > 2) {
$args = ();
foreach ($grouped as $key => $value) {
$parms = ([$value], ($args, 2, ()));
$grouped[$key] = ('array_group_by', $parms);
}
}
return $grouped;
}
$arr : 二维数组
$key: 需要分组的key
得到的结果是：
Array
(
[分组2]
=> Array (
[
0] => Array (
=> 1
=> 2
=> 1
=> 2016-12-02 11:39:34
=> 分组2 )
[
1] => Array (
=> 2
=> 31
=> 2
=> 2016-12-12 11:39:50
=> 分组2 )
[
2] => Array (
=> 3
=> 31
=> 4
=> 2016-12-02 11:40:01
=> 分组2 )
)
[分组1]
=> Array (
[
0] => Array (
=> 4
=> 2
=> 5
=> 2016-12-07 10:21:40
=> 分组1 )
[
1] => Array (
=> 5
=> 2
=> 3
=> 2016-12-07 10:21:51
=> 分组1 )
)
)
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