The difference between various array merging methods in php

PHP is a commonly used programming language, in which arrays are commonly used data structures. PHP provides a variety of array merging methods, and this article will introduce the differences between them in detail.

1. array_merge()

array_merge() function is used to merge two or more arrays. It concatenates all arrays and returns a new array. If two or more arrays have the same key, the later key will overwrite the earlier key.

Sample code:

$arr1 = array('a', 'b', 'c');
$arr2 = array('d', 'e', 'f');
$result = array_merge($arr1, $arr2);
print_r($result);

Output result:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => d
    [4] => e
    [5] => f
)

2. array_merge_recursive()

array_merge_recursive() function is used to merge two or multiple arrays, unlike the array_merge() function, if two or more arrays have the same key, they will be merged into one array instead of overwritten.

Sample code:

$arr1 = array('a' => array('x'), 'b' => array('y'));
$arr2 = array('a' => array('z'), 'b' => array('w'));
$result = array_merge_recursive($arr1, $arr2);
print_r($result);

Output result:

Array
(
    [a] => Array
        (
            [0] => x
            [1] => z
        )

    [b] => Array
        (
            [0] => y
            [1] => w
        )
)

3. array_combine()

array_combine() function is used to combine two Arrays are combined into an array of key-value pairs. The values ​​of the first array serve as keys and the values ​​of the second array serve as values.

Sample code:

$keys = array('a', 'b', 'c');
$values = array(1, 2, 3);
$result = array_combine($keys, $values);
print_r($result);

Output result:

Array
(
    [a] => 1
    [b] => 2
    [c] => 3
)

4. array_replace()

array_replace() function is used to use the following Array replaces the previous array. If two arrays have the same key, the later value will overwrite the earlier value.

Sample code:

$arr1 = array('a' => 1, 'b' => 2, 'c' => 3);
$arr2 = array('b' => 4);
$result = array_replace($arr1, $arr2);
print_r($result);

Output result:

Array
(
    [a] => 1
    [b] => 4
    [c] => 3
)

5. array_replace_recursive()

array_replace_recursive() function is used to use the following Array recursively replaces the previous array. If two arrays have the same key, the later value will recursively replace the earlier value.

Sample code:

$arr1 = array('a' => array('x'), 'b' => array('y'));
$arr2 = array('a' => array('z'), 'b' => array('w'));
$result = array_replace_recursive($arr1, $arr2);
print_r($result);

Output result:

Array
(
    [a] => Array
        (
            [0] => z
        )

    [b] => Array
        (
            [0] => w
        )

)

Summary

In PHP, arrays are very important data structures. Mastering the use of different array merging functions will help you develop more efficient and reliable code. Before choosing which array merging function to use, you need to compare the functions based on actual needs and find the most appropriate method to solve the problem.

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