PHP笛卡尔积实现算法示例

　　本文实例讲述了PHP笛卡尔积实现算法。分享给大家供大家参考，具体如下：

　　 <?php $arr = array(array(1,3,4,5),array(3,5,7,9),array(76,6,1,0)); /** ** 实现二维数组的笛卡尔积组合 ** $arr 要进行笛卡尔积的二维数组 ** $str 最终实现的笛卡尔积组合,可不写 ** @return array **/ function cartesian($arr,$str = array()){ //去除第一个元素 $first = array_shift($arr); //判断是否是第一次进行拼接 if(count($str) > 1) { foreach ($str as $k => $val) { foreach ($first as $key => $value) { //最终实现的格式 1,3,76 //可根据具体需求进行变更 $str2[] = $val.,.$value; } } }else{ foreach ($first as $key => $value) { //最终实现的格式 1,3,76 //可根据具体需求进行变更 $str2[] = $value; } } //递归进行拼接 if(count($arr) > 0){ $str2 = cartesian($arr,$str2); } //返回最终笛卡尔积 return $str2; } $cartesian_product = cartesian($arr); print_r($cartesian_product); ?>

　　最终输出格式

　　Array
(
[0] => 1,3,76
[1] => 1,3,6
[2] => 1,3,1
[3] => 1,3,0
[4] => 1,5,76
[5] => 1,5,6
[6] => 1,5,1
[7] => 1,5,0
[8] => 1,7,76
[9] => 1,7,6
[10] => 1,7,1
[11] => 1,7,0
[12] => 1,9,76
[13] => 1,9,6
[14] => 1,9,1
[15] => 1,9,0
[16] => 3,3,76
[17] => 3,3,6
[18] => 3,3,1
[19] => 3,3,0
[20] => 3,5,76
[21] => 3,5,6
[22] => 3,5,1
[23] => 3,5,0
[24] => 3,7,76
[25] => 3,7,6
[26] => 3,7,1
[27] => 3,7,0
[28] => 3,9,76
[29] => 3,9,6
[30] => 3,9,1
[31] => 3,9,0
[32] => 4,3,76
[33] => 4,3,6
[34] => 4,3,1
[35] => 4,3,0
[36] => 4,5,76
[37] => 4,5,6
[38] => 4,5,1
[39] => 4,5,0
[40] => 4,7,76
[41] => 4,7,6
[42] => 4,7,1
[43] => 4,7,0
[44] => 4,9,76
[45] => 4,9,6
[46] => 4,9,1
[47] => 4,9,0
[48] => 5,3,76
[49] => 5,3,6
[50] => 5,3,1
[51] => 5,3,0
[52] => 5,5,76
[53] => 5,5,6
[54] => 5,5,1
[55] => 5,5,0
[56] => 5,7,76
[57] => 5,7,6
[58] => 5,7,1
[59] => 5,7,0
[60] => 5,9,76
[61] => 5,9,6
[62] => 5,9,1
[63] => 5,9,0
)

　　小编这里参考前面一篇《JavaScript笛卡尔积超简单实现算法》，给出一个php计算笛卡尔积的超简单算法示例如下：

　　 <?php function cartesian($arr1,$arr2){ $relarr = array(); foreach($arr1 as $v1){ foreach($arr2 as $v2){ array_push($relarr,$v1.,.$v2); } } return $relarr; } //用法示例 $a = array(1,2,3); $b = array(a,b,c); print_r(cartesian($a,$b)); ?>

　　运行结果：

　　Array
(
[0] => 1,a
[1] => 1,b
[2] => 1,c
[3] => 2,a
[4] => 2,b
[5] => 2,c
[6] => 3,a
[7] => 3,b
[8] => 3,c
)

　　更多关于PHP相关内容感兴趣的读者可查看本站专题：《PHP数学运算技巧总结》、《PHP数组(Array)操作技巧大全》、《PHP运算与运算符用法总结》、《php字符串(string)用法总结》、《PHP常用遍历算法与技巧总结》、《PHP数据结构与算法教程》及《php程序设计算法总结》

　　希望本文所述对大家PHP程序设计有所帮助。