1、專案中經常會用到獲取多維陣列某個特定鍵的所有值，經常的做法是迴圈獲取，今天在網上看到一個不用迴圈獲取的辦法。

/* 
author: [email protected] 
description: 根據某一特定鍵(下標)取出一維或多維陣列的所有值；不用迴圈的理由是考慮大陣列的效率，把陣列序列化，然後根據序列化結構的特點提取需要的字串 
*/  
function array_get_by_key(array $array, $string){  
    if (!trim($string)) return false;  
    preg_match_all("/\"$string\";\w{1}:(?:\d+:|)(.*?);/", serialize($array), $res);  
    return $res[1];  
}  
  
$r = array('id'=> 1, 's'=> 23, 'a' => array('s' => 123, array(1, 2, 's' => "asdasdgsadggsadg")));  
echo '<pre>';  
print_r (array_get_by_key($r, 's'));
 

2、下面這個方法，採用php的閉包語法。這個要在php5.3以上才可以執行

<?php
$arr = array('id'=> 1, 's'=> 23, 'a' => array('s' => 123, array(1, 2, 's' => "asdasdgsadggsadg"))); 

$result = array_filter($arr, function ($var) {   
  $found = false;
  array_walk_recursive($var, function ($item, $key) use (&$found) {  
    $found = $found || $key == "s";
  });
  return $found;
});

var_dump($result);
 

function searchMultiArray(array $array, $search, $mode = 'key') {
    $res = array();
    foreach (new RecursiveIteratorIterator(new RecursiveArrayIterator($array)) as $key => $value) {
        if ($search === ${${"mode"}}){
            if($mode == 'key'){
                $res[] = $value;
            }else{
                $res[] = $key;
            }
        }
    }
    return $res;
}

var_dump(searchMultiArray($arr, 's'));
 

function getArray($array, $index) {
    if (!is_array($array)) return null;
    if (isset($array[$index])) return $array[$index];
    foreach ($array as $item) {
        $return = getArray($item, $index);
        if (!is_null($return)) {
            return $return;
        }
    }
    return null;
}