php - PHP对多维数组的一个维度进行排序

Question

没什么好解释的，我直接上示例代码：

<?php
$array[0]['a'] = 3;
$array[0]['b'] = 2;
$array[0]['c'] = 4;
$array[0]['d'] = 1;

$array[1]['a'] = 4;
$array[1]['b'] = 2;
$array[1]['c'] = 3;
$array[1]['d'] = 1;

$array[2]['a'] = 1;
$array[2]['b'] = 2;
$array[2]['c'] = 4;
$array[2]['d'] = 3;
?>

排序后，它应该是这样的：

<?php

$array[0]['d'] = 1;
$array[0]['b'] = 2;
$array[0]['a'] = 3;
$array[0]['c'] = 4;


$array[1]['d'] = 1;
$array[1]['b'] = 2;
$array[1]['c'] = 3;
$array[1]['a'] = 4;

$array[2]['a'] = 1;
$array[2]['b'] = 2;
$array[2]['d'] = 3;
$array[2]['c'] = 4;
?>

我真的无法理解它。简而言之：我不想对整个数组进行排序，而是对数组的特定维度进行排序

Answer 1

用于foreach下一级，然后对每个子数组进行排序。有几种方法可以做到这一点：

foreach($arr as &$sub) asort($sub);
// OR
foreach($arr as $k=>$sub) asort($arr[$k]);
// OR
foreach(array_keys($arr) as $k) asort($arr[$k]);

Answer 2

您必须直接对索引进行排序：

ksort($array[0]);

对所有索引进行排序：

foreach($array as $index => $val){ 
    asort($val);
    $array[$index] = $val; 
}