Ask for an algorithm for the combination of two-dimensional array elements in PHP

$arr = array(    array('a','b','c'),    array('c','f'),    array('g','z'),    array('x','y'));//$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'),  ……)

Can it be implemented with a function?

//$arr：原始数组，$cNum：组合长度function getCombination($arr,$cNum){  ……}

Reply content:

$arr = array(    array('a','b','c'),    array('c','f'),    array('g','z'),    array('x','y'));//$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'),  ……)

Can it be implemented with a function?

//$arr：原始数组，$cNum：组合长度function getCombination($arr,$cNum){  ……}

Recursion?

$arr = array(    array('a', 'b', 'c'),    array('c', 'f'),    array('g', 'z'),    array('x', 'y'));//$arr：原始数组，$cNum：组合长度function getCombination($arr, $cNum) {    if ($cNum === 0) {        return return array(            array('a'),            array('b'),            array('c'),        );    } else {        $tmpArr2 = $arr;        $resultArr = array();        array_pop($tmpArr2);        $lastNewArr = getCombination($tmpArr2, $cNum - 1);        for ($i = 0; $i < count($lastNewArr); $i++) {            for ($j = 0; $j < count($arr[$cNum]); $j++) {                $tmpArr = $lastNewArr[$i];                $tmpArr[] = $arr[$cNum][$j];                $resultArr[] = $tmpArr;            }        }        return $resultArr;    }}print_r(getCombination($arr, count($arr) - 1));

Uh...... My current idea is to take the array that meets the set length, then the Cartesian product, and finally merge it into a new array ...
Three functions completed.

The problem with the main question is PHP计算二维数组笛卡尔积 , right? If so, take a look at the following code:

Class descartes{public $sourceArray;    Public $resultArray;        Public function __construct ($array, $result) {$this->sourcearray = $array;    $this->resultarray = $result;            Public Function Calcdescartes ($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; $i < $currentArrayCount; + + $i) {$currentArraySlice = Array_slice ($arrResult, 0, $arrResultCoun            T);            Array_push ($currentArraySlice, $currentArray [$i]);        $this->calcdescartes ($arrIndex + 1, $currentArraySlice); }}} $example = [[' A ', ' B ', ' C '], [' C ', ' F '], [' G ', ' Z '], [' X ', ' Y ']]; $result = []; $descartes = new Descart Es ($example, $result); $descartes->calcdescArtes (0, $result); Var_dump ($descartes->resultarray); 

