How to cross merge two arrays in php

In PHP, how to cross-merge two arrays? This problem is very common in data processing and program development. Cross-merging two arrays can enrich the data and provide a more diverse way of running the program. This article will introduce in detail how to use PHP to implement cross-merging of two arrays.

Before we begin, we need to understand what "cross-merge" is. Simply put, cross-merging is to cross-combine the elements of two arrays. For example, if we have two arrays:

$array1 = [1, 3, 5];
$array2 = [2, 4, 6];

then after cross merging The result should be:

$result = [1, 2, 3, 4, 5, 6];

Now let us see how to implement this process with PHP.

Method 1: Use for loop to achieve

First, we can use for loop to achieve cross-merging of two arrays. The specific steps are as follows:

1. Create a new empty array to store the results of cross-merging.
2. Use a for loop to traverse two arrays, and add elements with the same subscript in the two arrays to the new array each time.
3. If one of the arrays is longer than the other, then after the loop ends, the extra elements of the other array need to be added to the end of the new array.

The following is a sample code:

<?php
  // 定义两个数组
  $array1 = [1, 3, 5];
  $array2 = [2, 4, 6];

  // 计算两个数组的长度
  $len1 = count($array1);
  $len2 = count($array2);

  // 创建一个新的空数组
  $result = [];

  // 使用for循环遍历两个数组
  for ($i = 0; $i < $len1 || $i < $len2; $i++) {
      // 如果数组1的长度大于$i，则将数组1的第$i个元素添加到结果数组中
      if ($i < $len1) {
          $result[] = $array1[$i];
      }

      // 如果数组2的长度大于$i，则将数组2的第$i个元素添加到结果数组中
      if ($i < $len2) {
          $result[] = $array2[$i];
      }
  }

  // 输出结果数组
  print_r($result);
?>

The above code will output the following results:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)

Method 2: Use the array_map function to achieve

Except Using a for loop, we can also use PHP's built-in array_map function to implement cross merging. The array_map function can receive multiple arrays as parameters, pass elements with the same subscript in these arrays to a custom function for processing, and then return the processed results into a new array.

The specific steps are as follows:

1. Create a custom function for cross-merging multiple parameters.
2. Use the array_map function and pass two arrays to it as parameters. The custom function will receive elements with the same index in the two arrays as parameters and cross-merge them.

The following is a sample code:

<?php
  // 定义两个数组
  $array1 = [1, 3, 5];
  $array2 = [2, 4, 6];

  // 创建一个自定义函数，用于将多个参数交叉合并
  function cross_merge(...$arrays) {
      $len = count($arrays[0]);
      $result = [];

      // 遍历每个子数组
      for ($i = 0; $i < $len; $i++) {
          // 遍历每个参数
          foreach ($arrays as $array) {
              // 如果当前参数的下标小于数组的长度，则将当前参数的第$i个元素添加到结果数组中
              if ($i < count($array)) {
                  $result[] = $array[$i];
              }
          }
      }

      return $result;
  }

  // 使用array_map函数
  $result = array_map("cross_merge", $array1, $array2);

  // 输出结果数组
  print_r($result);
?>

The above code will output the following results:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)

Summary

Cross merge two arrays in the data It is a very practical technology in processing and program development. In PHP, we can use for loop or array_map function to achieve this. In general, the array_map function is more concise and efficient, but the way of using a for loop is more intuitive and easy to understand. According to actual needs, just choose the appropriate method to achieve cross-merging.

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