请教一个php中二维数组元素组合的算法

Question

$arr=array(
array('a','b','c'),
array('c','f'),
array('g','z'),
array('x','y')
);
//$arr子集元素长度可能会多一些
//将$arr的子集元素与$arr其他子集元素两两组合或者三三四四组合
//子集array('a','b','c')中的元素不需要组合
//两两组合
$newarr=array(
array('a','c'),
array('a','f'),
array('b','c'),
array('b','f'),
array('c','c'),
array('c','f'),
……
)
//三三组合
$newarr=array(
array('a','c','g'),
array('a','f','g'),
array('b','c','g'),
array('b','f','g'),
array('c','c','g'),
array('c','f','g'),
……
)
//四四组合
$newarr=array(
array('a','c','g','x'),
array('a','f','g','x'),
array('b','c','g','x'),
array('b','f','g','x'),
array('c','c','g','x'),
array('c','f','g','x'),
……
)
用一个函数可以实现吗？
//$arr：原始数组，$cNum：组合长度
functiongetCombination($arr,$cNum){
……
}

Answer 1

递归？$arr=array(array('a','b','c'),array('c','f'),array('g','z'),array('x','y'));//$arr：原始数组，$cNum：组合长度functiongetCombination($arr,$cNum){if($cNum===0){returnreturnarray(array('a'),array('b'),array('c'),);}else{$tmpArr2=$arr;$resultArr=array();array_pop($tmpArr2);$lastNewArr=getCombination($tmpArr2,$cNum-1);for($i=0;$i

Answer 2

题主的问题应该是PHP计算二维数组笛卡尔积吧？如果是的话，请看以下代码：classDescartes{public$sourceArray;public$resultArray;publicfunction__construct($array,$result){$this->sourceArray=$array;$this->resultArray=$result;}publicfunctioncalcDescartes($arrIndex,$arrResult){if($arrIndex>=count($this->sourceArray)){array_push($this->resultArray,$arrResult);return;}$currentArray=$this->sourceArray[$arrIndex];$currentArrayCount=count($currentArray);$arrResultCount=count($arrResult);for($i=0;$icalcDescartes($arrIndex+1,$currentArraySlice);}}}$example=[['a','b','c'],['c','f'],['g','z'],['x','y']];$result=[];$descartes=newDescartes($example,$result);$descartes->calcDescartes(0,$result);var_dump($descartes->resultArray);