php - 求一个一维数组中，n个元素的不同组合,并返回该数组

Question

array('a1','b2','c3','d4','e5','x1','y1','z1');
比如以上数组

我想要这个数组元素中三个元素的不同组合，例如下
array('a1','b2','c3');
array('a1','b2','d4');
array('a1','b2','e5');
array('a1','b2','x1');
array('a1','b2','y1');
....

并最终返回这样一个数组

array(

array('a1','b2','c3'),
array('a1','b2','d4'),
array('a1','b2','e5'),
array('a1','b2','x1'),
array('a1','b2','y1'),
......

)

Answer 1

三层foreach解决

$data = array('a1','b2','c3','d4','e5','x1','y1','z1');

foreach ($data as $k_1 => $v_1) {
    foreach ($data as $k_2 => $v_2) {
        foreach ($data as $k_3 => $v_3) {
            if ($v_1 !== $v_2 && $v_1 !== $v_3 && $v_2 !== $v_3) {
                var_dump([$v_1,$v_2,$v_3]);
            }
        }    
    }
}

Answer 2

排列组合嘛，三个数的索引的话终归是有大小的，把他们从小到大排列，
设为a b c d，然后（这是数学题了）

Answer 3

谢谢邀请。数学没学好，你去看看手册里面的数据排序／合并函数用法

Answer 4

<?php
$arr = array('a','b','c','d');
$result = array();
$t = getCombinationToString($arr, 3);
print_r($t);

function getCombinationToString($arr, $m) {
    if ($m ==1) {
        return $arr;
    }
    $result = array();

    $tmpArr = $arr;
    unset($tmpArr[0]);
    for($i=0;$i<count($arr);$i++) {
        $s = $arr[$i];
        $ret = getCombinationToString(array_values($tmpArr), ($m-1));

        foreach($ret as $row) {
            $result[] = $s . $row;
        }
    }

    return $result;
}
?>

Array
(

[0] => abc
[1] => abd
[2] => acc
[3] => acd
[4] => adc
[5] => add
[6] => bbc
[7] => bbd
[8] => bcc
[9] => bcd
[10] => bdc
[11] => bdd
[12] => cbc
[13] => cbd
[14] => ccc
[15] => ccd
[16] => cdc
[17] => cdd
[18] => dbc
[19] => dbd
[20] => dcc
[21] => dcd
[22] => ddc
[23] => ddd

)
给你一个思路吧

Answer 5

array('a1','b1','c1')和array('c1','a1','b1')算重复吗？