本文实例讲述了PHP实现数组的笛卡尔积运算。分享给大家供大家参考，具体如下：
数组的笛卡尔积在实际中还是挺有用处的，比如计算商品的规格时就经常用到，下面写一种实现方式，如下代码
$arr = array(
array(2),
array(6,7),
array('a','b','c')
);
function dikaer($arr){
$arr1 = array();
$result = array_shift($arr);
while($arr2 = array_shift($arr)){
$arr1 = $result;
$result = array();
foreach($arr1 as $v){
foreach($arr2 as $v2){
if(!is_array($v))$v = array($v);
if(!is_array($v2))$v2 = array($v2);
$result[] = array_merge_recursive($v,$v2);
}
}
}
return $result;
}
以上例子输出的结果如下：
Array
(
[0] => Array
(
[0] => 2
[1] => 6
[2] => a
)
[1] => Array
(
[0] => 2
[1] => 6
[2] => b
)
[2] => Array
(
[0] => 2
[1] => 6
[2] => c
)
[3] => Array
(
[0] => 2
[1] => 7
[2] => a
)
[4] => Array
(
[0] => 2
[1] => 7
[2] => b
)
[5] => Array
(
[0] => 2
[1] => 7
[2] => c
)
)
如果需要输出字符串形式的结果可以把代码改成这样
function dikaer($arr){
$arr1 = array();
$result = array_shift($arr);
while($arr2 = array_shift($arr)){
$arr1 = $result;
$result = array();
foreach($arr1 as $v){
foreach($arr2 as $v2){
$result[] = $v.','.$v2;
}
}
}
return $result;
}
输出结果如下所示：
Array ( [0] => 2,6,a [1] => 2,6,b [2] => 2,6,c [3] => 2,7,a [4] => 2,7,b [5] => 2,7,c )
希望本文所述对大家PHP程序设计有所帮助。
