Introduction to how to use the array_replace_recursive() function in the PHP function library

PHP is a popular web programming language with a rich library of functions that can help us handle different tasks. Among them, the array_replace_recursive() function is a function used to merge itself with another or multiple arrays. This function can recursively merge two or more arrays, including their key-value pairs and sub-arrays. This article will introduce how to use this function.

The basic syntax of the array_replace_recursive() function is as follows:

array_replace_recursive(array1, array2, array3......);

This function accepts multiple arrays as parameters, and the return value of the function is the merged array. Arrays are merged recursively, that is, it compares the keys and values ​​of the arrays recursively. If two keys match, their values ​​are merged recursively. If the value is an array, the arrays will be merged recursively until there are no subarrays left.

The following is an example:

$array1 = array(
    'fruit' => array(
        'apple' => 1,
        'orange' => 4,
        'banana' => 3
    ),
    'vegetable' => array(
        'potato' => 2,
        'broccoli' => 1,
        'carrot' => 4
    )
);

$array2 = array(
    'fruit' => array(
        'orange' => 2
    ),
    'vegetable' => array(
        'potato' => 3,
        'broccoli' => 2,
        'carrot' => 1
    )
);

$result = array_replace_recursive($array1, $array2);

print_r($result);

The output result is as follows:

Array
(
    [fruit] => Array
        (
            [apple] => 1
            [orange] => 2
            [banana] => 3
        )

    [vegetable] => Array
        (
            [potato] => 3
            [broccoli] => 2
            [carrot] => 1
        )

)

As you can see, array $array2 recursively overwrites the corresponding key value of array $array1, and other keys Not affected. Using this function allows us to merge arrays more conveniently.

It should be noted that when using the array_replace_recursive() function to merge arrays, if the same key appears in multiple arrays, the later array will overwrite the previous array. The keys of the array must be strings or integers, otherwise a warning will be generated.

Also, if you want to keep the keys and values ​​that exist in the destination array and add the keys and values ​​that do not exist in the source array to the destination array, you can use the array_merge_recursive() function. This function is similar to the array_replace_recursive() function, except that the latter overwrites existing keys and values.

To sum up, the array_replace_recursive() function is a very practical function. It can merge two or more arrays recursively, overwriting or preserving existing keys and values ​​in the way you expect. This function is worth using if you need to merge PHP arrays when working with them.

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