[PHP] PHP实现数组的笛卡尔积运算示例

$arr = array(
  array(2),
  array(6,7),
  array('a','b','c')
);
function dikaer($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;
}

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
  )
)

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;
}

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
)