php自定义函数生成笛卡尔积的方法

这篇文章主要介绍了PHP基于自定义函数生成笛卡尔积的方法,结合具体实例形式分析了php使用数组运算模拟集合实现笛卡尔积运算的相关操作技巧,需要的朋友可以参考下

本文实例讲述了PHP基于自定义函数生成笛卡尔积的方法。分享给大家供大家参考，具体如下：

<?php
  $color = array('red', 'green');
  $size = array(39, 40, 41);
  $local = array('beijing', 'shanghai');
  echo "<pre>";
  print_r(combineDika($color, $size, $local));
  /**
   * 所有数组的笛卡尔积
   *
   * @param unknown_type $data
   */
  function combineDika() {
    $data = func_get_args();
    $cnt = count($data);
    $result = array();
    foreach($data[0] as $item) {
      $result[] = array($item);
    }
    for($i = 1; $i < $cnt; $i++) {
      $result = combineArray($result,$data[$i]);
    }
    return $result;
  }
  /**
   * 两个数组的笛卡尔积
   *
   * @param unknown_type $arr1
   * @param unknown_type $arr2
   */
  function combineArray($arr1,$arr2) {
    $result = array();
    foreach ($arr1 as $item1) {
      foreach ($arr2 as $item2) {
        $temp = $item1;
        $temp[] = $item2;
        $result[] = $temp;
      }
    }
    return $result;
  }
?>

运行结果：

Array
(
  [0] => Array
    (
      [0] => red
      [1] => 39
      [2] => beijing
    )
  [1] => Array
    (
      [0] => red
      [1] => 39
      [2] => shanghai
    )
  [2] => Array
    (
      [0] => red
      [1] => 40
      [2] => beijing
    )
  [3] => Array
    (
      [0] => red
      [1] => 40
      [2] => shanghai
    )
  [4] => Array
    (
      [0] => red
      [1] => 41
      [2] => beijing
    )
  [5] => Array
    (
      [0] => red
      [1] => 41
      [2] => shanghai
    )
  [6] => Array
    (
      [0] => green
      [1] => 39
      [2] => beijing
    )
  [7] => Array
    (
      [0] => green
      [1] => 39
      [2] => shanghai
    )
  [8] => Array
    (
      [0] => green
      [1] => 40
      [2] => beijing
    )
  [9] => Array
    (
      [0] => green
      [1] => 40
      [2] => shanghai
    )
  [10] => Array
    (
      [0] => green
      [1] => 41
      [2] => beijing
    )
  [11] => Array
    (
      [0] => green
      [1] => 41
      [2] => shanghai
    )
)

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