Mastering PHP’s array_replace: How to Merge Arrays Efficiently

Explanation

The array_replace() function replaces the values of the first array with values from subsequent arrays that share the same keys. If a key exists only in a later array, that element is added to the result. Keys present only in the first array remain unchanged. The function processes multiple replacement arrays sequentially, with later arrays overriding earlier values. It operates non‑recursively, meaning it replaces values regardless of their type.

Parameter Description

array1 : The original array whose values may be replaced.

array2 : The array providing replacement values.

... : Additional arrays whose values will further replace previous ones, processed in order.

Return Value

The function returns the resulting array after all replacements. If an error occurs, NULL is returned.

Example

<?php
$base = array("orange", "banana", "apple", "raspberry");
$replacements = array(0 => "pineapple", 4 => "cherry");
$replacements2 = array(0 => "grape");
$basket = array_replace($base, $replacements, $replacements2);
print_r($basket);
?>

Output

Array
(
    [0] => grape
    [1] => banana
    [2] => apple
    [3] => raspberry
    [4] => cherry
)