我已经疯狂地尝试了两天才完成这个任务，也许你可以帮助我。这是一个关于马赛投注排列的问题。每当用户进行游戏时，我会得到一个多维数组（2级）。第一级包含比赛ID，第二级包含用户为该比赛选择的三匹马。它看起来像这样：
$play = array
(
'4' => array(7, 32),
'8' => array(4),
'2' => array(9),
'12' => array('5'),
'83' => array('10', '11', '12', ''),
'9' => array('3'),
);
我需要知道那次游戏的所有可能组合。这可以通过以下函数轻松完成：
function permutations(array $array)
{
switch (count($array)) {
case 1:
return $array[0];
break;
case 0:
throw new InvalidArgumentException('Requires at least one array');
break;
}
$a = array_shift($array);
$b = permutations($array);
$return = array();
foreach ($a as $key => $v) {
if(is_numeric($v))
{
foreach ($b as $key2 => $v2) {
$return[] = array_merge(array($v), (array) $v2);
}
}
}
return $return;
}
这将返回一个包含所有可能组合的数组，非常美观。到目前为止一切顺利，结果如下：
Array
(
[0] => Array
(
[0] => 7
[1] => 4
[2] => 9
[3] => 5
[4] => 10
[5] => 3
)
[1] => Array
(
[0] => 7
[1] => 4
[2] => 9
[3] => 5
[4] => 11
[5] => 3
)
[2] => Array
(
[0] => 7
[1] => 4
[2] => 9
[3] => 5
[4] => 12
[5] => 3
)
[3] => Array
(
[0] => 32
[1] => 4
[2] => 9
[3] => 5
[4] => 10
[5] => 3
)
[4] => Array
(
[0] => 32
[1] => 4
[2] => 9
[3] => 5
[4] => 11
[5] => 3
)
[5] => Array
(
[0] => 32
[1] => 4
[2] => 9
[3] => 5
[4] => 12
[5] => 3
)
)
我的问题：我需要每匹马的数组“key”为“race ID”，而不是0、1、2、3。我需要的结果应该像这样：
Array
(
[0] => Array
(
[4] => 7
[8] => 4
[2] => 9
[12] => 5
[83] => 10
[9] => 3
)
[1] => Array
(
[4] => 7
[8] => 4
[2] => 9
[12] => 5
[83] => 11
[9] => 3
)
[2] => Array
(
[4] => 7
[8] => 4
[2] => 9
[12] => 5
[83] => 12
[9] => 3
)
[3] => Array
(
[4] => 32
[8] => 4
[2] => 9
[12] => 5
[83] => 10
[9] => 3
)
[4] => Array
(
[4] => 32
[8] => 4
[2] => 9
[12] => 5
[83] => 11
[9] => 3
)
[5] => Array
(
[4] => 32
[8] => 4
[2] => 9
[12] => 5
[83] => 12
[9] => 3
)
)
如何实现这个功能？我知道这是一篇较长的帖子，但我需要绘制它。我在函数递归方面遇到了问题，并且在每个循环中都完全迷失了方向。