PHP：如何获得一维数组的所有可能的组合？

Question

可能重复：
algorithm that will take numbers or words and find all possible combinations
Combinations, Dispositions and Permutations in PHP

我读过/试过所以建议答案，这其中没有一个解决问题的很多

$array = array('Alpha', 'Beta', 'Gamma'); 

如何获得所有可能的组合？

预期输出：

array('Alpha', 
     'Beta', 
     'Gamma', 
     'Alpha Beta', 
     'Alpha Gamma', 
     'Beta Alpha', 
     'Beta Gamma', 
     'Gamma Alpha', 
     'Gamma Beta', 
     'Alpha Beta Gamma', 
     'Alpha Gamma Beta', 
     'Beta Alpha Gamma', 
     'Beta Gamma Alpha', 
     'Gamma Alpha Beta', 
     'Gamma Beta Alpha') 

注：我在寻找答案应该包括所有组合和各种不同的安排。例如：'Alpha Beta'和'Beta Alpha'是2个不同的字符串，它们都应该在输出数组中。

在此先感谢

Answer 1

我相信你的教授将这种解决方案更幸福：

<?php 

$array = array('Alpha', 'Beta', 'Gamma', 'Sigma'); 

function depth_picker($arr, $temp_string, &$collect) { 
    if ($temp_string != "") 
     $collect []= $temp_string; 

    for ($i=0; $i<sizeof($arr);$i++) { 
     $arrcopy = $arr; 
     $elem = array_splice($arrcopy, $i, 1); // removes and returns the i'th element 
     if (sizeof($arrcopy) > 0) { 
      depth_picker($arrcopy, $temp_string ." " . $elem[0], $collect); 
     } else { 
      $collect []= $temp_string. " " . $elem[0]; 
     } 
    } 
} 

$collect = array(); 
depth_picker($array, "", $collect); 
print_r($collect); 

?> 

这解决了它：

Array 
(
    [0] => Alpha 
    [1] => Alpha Beta 
    [2] => Alpha Beta Gamma 
    [3] => Alpha Beta Gamma Sigma 
    [4] => Alpha Beta Sigma 
    [5] => Alpha Beta Sigma Gamma 
    [6] => Alpha Gamma 
    [7] => Alpha Gamma Beta 
    [8] => Alpha Gamma Beta Sigma 
    [9] => Alpha Gamma Sigma 
    [10] => Alpha Gamma Sigma Beta 
    [11] => Alpha Sigma 
    [12] => Alpha Sigma Beta 
    [13] => Alpha Sigma Beta Gamma 
    [14] => Alpha Sigma Gamma 
    [15] => Alpha Sigma Gamma Beta 
    [16] => Beta 
    [17] => Beta Alpha 
    [18] => Beta Alpha Gamma 
    [19] => Beta Alpha Gamma Sigma 
    [20] => Beta Alpha Sigma 
    [21] => Beta Alpha Sigma Gamma 
    [22] => Beta Gamma 
    [23] => Beta Gamma Alpha 
    [24] => Beta Gamma Alpha Sigma 
    [25] => Beta Gamma Sigma 
    [26] => Beta Gamma Sigma Alpha 
    [27] => Beta Sigma 
    [28] => Beta Sigma Alpha 
    [29] => Beta Sigma Alpha Gamma 
    [30] => Beta Sigma Gamma 
    [31] => Beta Sigma Gamma Alpha 
    [32] => Gamma 
    [33] => Gamma Alpha 
    [34] => Gamma Alpha Beta 
    [35] => Gamma Alpha Beta Sigma 
    [36] => Gamma Alpha Sigma 
    [37] => Gamma Alpha Sigma Beta 
    [38] => Gamma Beta 
    [39] => Gamma Beta Alpha 
    [40] => Gamma Beta Alpha Sigma 
    [41] => Gamma Beta Sigma 
    [42] => Gamma Beta Sigma Alpha 
    [43] => Gamma Sigma 
    [44] => Gamma Sigma Alpha 
    [45] => Gamma Sigma Alpha Beta 
    [46] => Gamma Sigma Beta 
    [47] => Gamma Sigma Beta Alpha 
    [48] => Sigma 
    [49] => Sigma Alpha 
    [50] => Sigma Alpha Beta 
    [51] => Sigma Alpha Beta Gamma 
    [52] => Sigma Alpha Gamma 
    [53] => Sigma Alpha Gamma Beta 
    [54] => Sigma Beta 
    [55] => Sigma Beta Alpha 
    [56] => Sigma Beta Alpha Gamma 
    [57] => Sigma Beta Gamma 
    [58] => Sigma Beta Gamma Alpha 
    [59] => Sigma Gamma 
    [60] => Sigma Gamma Alpha 
    [61] => Sigma Gamma Alpha Beta 
    [62] => Sigma Gamma Beta 
    [63] => Sigma Gamma Beta Alpha 
)