PHP array_replace_recursive() Function

The array_replace_recursive() is an inbuilt function in PHP that replaces the values of the first array with the values from following arrays recursively.
It performs the replacement based on the below rules:

• If a key from the first array exists in the second array, then the value corresponding to that key of the first array will be replaced by the value of the second array.
• If the key exists in the second array but not in the first array then it will be created in the first array.
• If a key only exists in the first array then it will be left as it is.
• If several arrays are passed for replacement, they will be processed in order, the later array overwriting the previous values.

Syntax:

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

Parameters: This function accepts a list of arrays as parameters where the first parameter is compulsory and rest are optional.

Return Value: It returns the modified array, or NULL if an error occurs.

Example:

Input: $array1 = array("a"=>array("red"), 
                       "b"=>array("green"));
       $array2 = array("a"=>array("yellow"), 
                       "b"=>array("black"));
Output: Array ( 
                [a] => Array ( [0] => yellow ) 
                [b] => Array ( [0] => black  ) 
              )

Below program illustrate the array_replace_recursive() function:

<?php

// PHP program to illustrate array_replace_recursive()
// function

$array1 = array( "a" => array("red"),
            "b" => array("green", "blue"));
$array2=array( "a" => array("yellow"),
                    "b" => array("black"));
$array3=array("a" => array("orange"),
                 "b" => array("burgundy"));

print_r(array_replace_recursive($array1, $array2, $array3));

?>

Output:

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

    [b] => Array
        (
            [0] => burgundy
            [1] => blue
        )

)

Reference:
http://php.net/manual/en/function.array-replace-recursive.php