array_replace_recursive() without creation of keys

Question

In PHP, array_replace_recursive() does two things according to the documentation:

• 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.

Is there an alternative that only does the replacement, and doesn't create new keys?

For example:

$array = [
  'apple' => TRUE,
  'pear' => TRUE,
  'basket' => [
    'banana' => TRUE,
  ],
  'punnet' => [
    'strawberry' => TRUE,
  ],
];

$replacement = [
  'banana' => [
    'REPLACEMENT!'
  ],
];

The result should be:

$array = [
  'apple' => TRUE,
  'pear' => TRUE,
  'basket' => [
    'banana' => [
      'REPLACEMENT!'
    ],
  ],
  'punnet' => [
    'strawberry' => TRUE,
  ],
];

Answer 1

This does what I needed:

array_walk_recursive($array, function(&$value, $key, $replacements) {
  if (isset($replacements[$key])) {
    $value = $replacements[$key];
  }
}, ['replace' => 'replacement']);

Answer 2

You will need to use array_intersect_key() to create an array that contains only the keys that are in the two arrays, then you can merge.

$array1 = [
    'a' => 1,
    'b' => 2,
    'c' => 3,
    'd' => 4,
];

$array2 = [
    'b' => 14,
    'c' => 70,
    'f' => 5,
];

// $array2 has to be the first arguments for $inter to have its value instead of the value of $array1
$inter = array_intersect_key($array2, $array1);

$merged = array_replace_recursive($array1, $inter);

// Merged will be: 
[
    'a' => 1,
    'b' => 14,
    'c' => 70,
    'd' => 4,
];

• array_intersect_key

EDIT For this to work recursively, you can use this function found here

/** 
* Recursively computes the intersection of arrays using keys for comparison.
* 
* @param   array $array1 The array with master keys to check.
* @param   array $array2 An array to compare keys against.
* @return  array associative array containing all the entries of array1 which have keys that are present in array2.
**/
function array_intersect_key_recursive(array $array1, array $array2) {
    $array1 = array_intersect_key($array1, $array2);

    foreach ($array1 as $key => &$value) {
        if (is_array($value) && is_array($array2[$key])) {
            $value = array_intersect_key_recursive($value, $array2[$key]);
        }
    }

    return $array1;
}