Simple and clear method to use PHP array_merge_recursive() function

When programming in PHP, we often need to merge arrays. PHP provides the array_merge() function to complete array merging, but when the same key exists in the array, this function will overwrite the original value. In order to solve this problem, PHP also provides an array_merge_recursive() function in the language, which can merge arrays and retain the values ​​of the same keys, making the design of the program more flexible.

array_merge_recursive() function can merge multiple arrays and merge values ​​with the same key into one array. During the merge process, the function recursively searches the arrays, merges the values ​​for the same key into a new array, and appends the new array's values ​​to the end of the old array. This retains the values ​​for the same keys in the original array and merges them in the new array.

The following is a detailed introduction to the use of the array_merge_recursive() function:

Syntax:

array array_merge_recursive (array $array1 [, array $...])

Parameters:

array1: required, the first array to be merged. It can also be followed by multiple arrays.

Return value:

This function returns the merged array.

Example:

<?php
$arr1 = array('name'=>'小明','age'=>18,'school'=>array('name'=>'清华大学','major'=>'计算机'));
$arr2 = array('name'=>'小红','school'=>array('name'=>'北京大学','city'=>'北京'),'age'=>20);
$result = array_merge_recursive($arr1, $arr2);
print_r($result);
?>

Output result:

Array
(
    [name] => Array
        (
            [0] => 小明
            [1] => 小红
        )

    [age] => Array
        (
            [0] => 18
            [1] => 20
        )

    [school] => Array
        (
            [name] => Array
                (
                    [0] => 清华大学
                    [1] => 北京大学
                )

            [major] => 计算机
            [city] => 北京
        )

)

As can be seen from the above example code, by using the array_merge_recursive() function, we can merge $arr1 and $arr2 The arrays are merged, and the merged result is stored in the $result variable. In the resulting array, we can see that the values ​​for the same key 'name' and 'age' are retained and merged into an array containing two values, while the values ​​under the same key 'school' are also merged into a new array.

In short, the array_merge_recursive() function is a very useful function in PHP programming. It can merge multiple arrays and retain the values ​​of the same keys. It is an essential tool for us to write flexible and efficient programs.

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