根据值解析PHP数组

Question

--- AIM ---

我有一个像这样的数组

$codes = array(
            array('type'=>1,'id'=>'qcdv'),
            array('type'=>2,'id'=>'thcd'),
            array('type'=>2,'id'=>'ngjd'),
            array('type'=>1,'id'=>'mhkx'),
            array('type'=>3,'id'=>'tnfr') /* many more elements*/
          );

并且所需的输出是

Array(
    [0] => Array ()
    [1] => Array (
        [0] => qcdv 
        [1] => mhkx ) 
    [2] => Array(
            [0] => thcd 
            [1] => ngjd
        )
    [3] => Array (
        [0] => tnfr
    )
) 

按类型键区分。

- 我现在试过什么 -

$codes = array(
    array('type'=>1,'id'=>'qcdv'),
    array('type'=>2,'id'=>'thcd'),
    array('type'=>2,'id'=>'ngjd'),
    array('type'=>1,'id'=>'mhkx'),
    array('type'=>3,'id'=>'tnfr')
);
$by_type=array(array(),array(),array(),array()); /* unable to digest this line */
foreach($codes as $code) { 
    array_push($by_type[$code['type']],$code['id']);
}
print_r($by_type);

它提供了正确的输出，但类型键范围是不固定所以我无法使用

$by_type=array(array(),array(),array(),array());

还有其他有效方法吗？

Answer 1

<?php

$codes = array(
            array('type'=>1,'id'=>'qcdv'),
            array('type'=>2,'id'=>'thcd'),
            array('type'=>2,'id'=>'ngjd'),
            array('type'=>1,'id'=>'mhkx'),
            array('type'=>3,'id'=>'tnfr')
          );


$array = array();
foreach( $codes as $v) {
$array[$v['type']][] = $v['id'];
}

print_r($array);

Answer 2

这段代码可以解决问题：

$output = array();
foreach ($codes as $idx1 => $array2)
{
    $k = $array2['type'];
    $v = $array2['id'];
    if (!isset($output[$k])) $output[$k] = array();
    $output[$k][] = $v;
}

Answer 3

 <?php

$codes = array(
            array('type'=>1,'id'=>'qcdv'),
            array('type'=>2,'id'=>'thcd'),
            array('type'=>2,'id'=>'ngjd'),
            array('type'=>1,'id'=>'mhkx'),
            array('type'=>3,'id'=>'tnfr') /* many more elements*/
          );

          $result = array();
          foreach($codes as $code)
          {
            $result[$code['type']][] = $code['id']; 
          }

          print_r($result);