How does the array_merge() function of PHP array merging work?

PHP’s array_merge() function merges two or more arrays into a new array. Create a new array. Iterate over the arrays to be merged. Add each element to a new array, overwriting existing elements if the keys are the same. Returns a new array containing all merged elements.

PHP array merge array_merge() function revealed

Introduction

array_merge() The function is used to merge two or more arrays into a new array. It is a very useful function that is often used to manipulate data and generate new arrays.

Syntax

array_merge(array1, array2, ..., arrayn);

Among them:

• array1, array2, ... , arrayn: The array to be merged

Working principle

array_merge() The function of the function is:

1. Create a new array.
2. Traverse each array to be merged.
3. Add each element to a new array, overwriting existing elements if the elements have the same key.

Return value

array_merge() The function returns a new array containing all elements merged from all input arrays .

Practical case

The following is an example of using the array_merge() function to merge two arrays:

<?php

$array1 = ['foo' => 'bar', 'baz' => 'qux'];
$array2 = ['foo' => 'new_bar', 'cat' => 'dog'];

$mergedArray = array_merge($array1, $array2);

print_r($mergedArray);
// 输出：
// Array
// (
//     [foo] => new_bar
//     [baz] => qux
//     [cat] => dog
// )
?>

In the output , we can see that the key of foo is overwritten because its value was updated in array2.

Note:

• array_merge() The function does not modify the original array.
• If the object to be merged is an array, but not an array key, you can use the array_merge_recursive() function.

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