多維數組：如何建立一個遞歸數（）

Question

我有一個多維數組：

membership = array(5) { 
[0]=> array(4) { [0]=> string(21) "Group A" [1]=> string(9) "10/1/2011" [2]=> string(9) "3/31/2012" [3]=> string(8) "00004130" } 
[1]=> array(4) { [0]=> string(22) "Group B" [1]=> string(8) "4/1/2011" [2]=> string(9) "9/30/2011" [3]=> string(8) "00005005" } 
[2]=> array(4) { [0]=> string(22) "Group A" [1]=> string(9) "10/1/2010" [2]=> string(9) "3/31/2011" [3]=> string(8) "00004130" } 
[3]=> array(4) { [0]=> string(22) "Group B" [1]=> string(8) "4/1/2010" [2]=> string(9) "9/30/2010" [3]=> string(8) "00005005" } 
[4]=> array(4) { [0]=> string(22) "Group B" [1]=> string(8) "10/1/2010" [2]=> string(9) "3/31/2011" [3]=> string(8) "00005005" } 
} 

我需要發現哪一組成員陣列中出現了多少次。

PHP的計數（）沒有遞歸功能，但它是如果它沒有輸出將是理想的（即，[ '組A'] => 2 [ 'B組'] => 3）。

我想過使用array_diff_uassoc（）但我只是不確定。所以我覺得在我漫無目的地走錯路之前尋求一些幫助是明智的。我確信有不止一種方法，但我總是在SO上找到非常有趣的編碼概念。

我正在運行php 5.3.5預先感謝您的建議和幫助。

Answer 1

這應該做的伎倆用最少的代碼：

$memberships = array(); // Your multi-dimensional array 

foreach($memberships as $membership) 
{ 
    $count[$membership[0]]++; 
} 

var_dump($count) 

對不起，我遲到後BTW，我想test it，使肯定它會按預期工作。

輸出是：

array(2) { 
    ["Group A"]=> 
    int(2) 
    ["Group B"]=> 
    int(3) 
} 

Answer 2

給出你有什麼，就是這樣。甚至不需要是遞歸的，因爲你的數組只是2D

<?php 
$membership = array( 
    array("Group A","10/1/2011","3/31/2012","00004130"), 
    array("Group B","4/1/2011","9/30/2011","00005005"), 
    array("Group A","10/1/2010","3/31/2011","00004130"), 
    array("Group B","4/1/2010","9/30/2010","00005005"), 
    array("Group B","10/1/2010","3/31/2011","00005005") 
); 

//initialize array for safety 
$count = array(); 

//loop through each item 
foreach($membership as $row){ 

    //check if group exists in count array 
    $group = $row[0]; 
    $groupExists = array_key_exists($group,$count); 

    if($groupExists){ 
     //if we've crossed paths before, just add 1 
     $count[$group]++; 
    } else { 
     //otherwise, let's start with 1 
     $count[$group]=1; 
    } 
} 

var_dump($count); 

//output dump should look like 
array(2) { 
    ["Group A"]=> int(2) 
    ["Group B"]=> int(3) 
}