笛卡尔积 php,PHP笛卡尔积实现算法示例

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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：

$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 =>

foreach (first as key =>

//最终实现的格式 1,3,76

//可根据具体需求进行变更

str2[] = val.’,’.

}

}

}else{

foreach (first as key =>

//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,

}

//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：

function cartesian(arr1,arr2){

$relarr = array();

foreach(arr1 as v1){

foreach(arr2 as v2){

array_push(relarr,v1.”,”.

}

}

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

)

希望本文所述对大家PHP程序设计有所帮助。

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