php从给定数组生成所有组合 [英] php generate all combinations from given array

问题描述

转换此PHP数组的最简单方法是什么

What is the simplest way to convert this PHP array

$a = array('A' => array(1, 2),
           'B' => array(3, 4),
           'C' => array(5));

对此:

$result = array(
    array('A' => 1, 'B' => 3, 'C' => 5),
    array('A' => 1, 'B' => 4, 'C' => 5),
    array('A' => 2, 'B' => 3, 'C' => 5),
    array('A' => 2, 'B' => 4, 'C' => 5),
);

在开发期间，

$a可能有许多不同的keys我不知道.所以我需要 生成给定数组中的所有组合.

$a may have many different keys I don't know during development time. So I need to generate all combinations in given array.

更新:

我必须基于传入数组生成URLs.所以我不知道在开发期间会得到多少个参数.我只有参数数组，例如.

I have to generate URLs based in incoming array. So I don't know how many parameters I will get during development time. I have only array of parameters, it can be e.g.

$a = array('A' => array(5,3, 1));

结果将是:

$result = array(
    array('A' => 5),
    array('A' => 3),
    array('A' => 1));

或

$a = array('X' => array(5), 'D' => array(4, 7));

结果将是:

$result = array(
    array('X' => 5, 'D' => 4),
    array('X' => 5, 'D' => 7));

推荐答案

喜欢这个:

$a = array('A' => array(1, 2),
           'B' => array(3, 4),
           'C' => array(5));

function get_combinations($arrays) {
    $result = array(array());
    foreach ($arrays as $property => $property_values) {
        $tmp = array();
        foreach ($result as $result_item) {
            foreach ($property_values as $property_value) {
                $tmp[] = array_merge($result_item, array($property => $property_value));
            }
        }
        $result = $tmp;
    }
    return $result;
}

输出

var_dump(get_combinations($a));

array (size=4)
  0 => 
    array (size=3)
      'A' => int 1
      'B' => int 3
      'C' => int 5
  1 => 
    array (size=3)
      'A' => int 1
      'B' => int 4
      'C' => int 5
  2 => 
    array (size=3)
      'A' => int 2
      'B' => int 3
      'C' => int 5
  3 => 
    array (size=3)
      'A' => int 2
      'B' => int 4
      'C' => int 5

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