array_replace_recursive

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

array_replace_recursive — Replaces elements from passed arrays into the first array recursively

Description

function array_replace_recursive(array $array, array ...$replacements): array

array_replace_recursive() replaces the values of array with the same values from all the following arrays. If a key from the first array exists in the second array, its value will be replaced by the value from the second array. If the key exists in the second array, and not the first, it will be created in the first array. If a key only exists in the first array, it will be left as is. If several arrays are passed for replacement, they will be processed in order, the later array overwriting the previous values.

array_replace_recursive() is recursive : it will recurse into arrays and apply the same process to the inner value.

When the value in the first array is scalar, it will be replaced by the value in the second array, may it be scalar or array. When the value in the first array and the second array are both arrays, array_replace_recursive() will replace their respective value recursively.

Parameters

array: The array in which elements are replaced.
replacements: Arrays from which elements will be extracted.

Return Values

Returns an array.

Examples

Example #1 array_replace_recursive() example

<?php
$base = array('citrus' => array("orange"), 'berries' => array("blackberry", "raspberry"));
$replacements = array('citrus' => array('pineapple'), 'berries' => array('blueberry'));

$basket = array_replace_recursive($base, $replacements);
print_r($basket);

$basket = array_replace($base, $replacements);
print_r($basket);
?>

The above example will output:

Array
(
    [citrus] => Array
        (
            [0] => pineapple
        )

    [berries] => Array
        (
            [0] => blueberry
            [1] => raspberry
        )

)
Array
(
    [citrus] => Array
        (
            [0] => pineapple
        )

    [berries] => Array
        (
            [0] => blueberry
        )

)

Example #2 array_replace_recursive() and recursive behavior

<?php
$base = array('citrus' => array("orange") , 'berries' => array("blackberry", "raspberry"), 'others' => 'banana' );
$replacements = array('citrus' => 'pineapple', 'berries' => array('blueberry'), 'others' => array('litchis'));
$replacements2 = array('citrus' => array('pineapple'), 'berries' => array('blueberry'), 'others' => 'litchis');

$basket = array_replace_recursive($base, $replacements, $replacements2);
print_r($basket);

?>

The above example will output:

Array
(
    [citrus] => Array
        (
            [0] => pineapple
        )

    [berries] => Array
        (
            [0] => blueberry
            [1] => raspberry
        )

    [others] => litchis
)

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User Contributed Notes 1 note

down

Pau Prat Torrella ¶

6 years ago

Note that function will NOT replace a sub-tree from you $array1 if its value in $array2 is an empty array. 
Even tho the key for this dimension is technically 'set'. 

(I suppose it treats it as just another recursive level to dive in, finding no key to compare, backtracking while leaving this sub-tree alone)

For example:

$array1  = ['first' => ['second' => 'hello']];
$array2  = ['first' => []];              
$result = array_replace_recursive($array1, $array2);

$result is still: ['first' => ['second' => 'hello']].