README

Installation

composer require rikudou/array-merge-recursive

Description

The php function array_merge_recursive behaves a little confusingly and not at all like array_merge.

Example of confusing behavior:

<?php

$array1 = [
    'test' => 'test'
];

$array2 = [
    'test' => 'test2'
];

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

// $result = 
// array(1) {
//   'test' =>
//   array(2) {
//     [0] =>
//     string(4) "test"
//     [1] =>
//     string(5) "test2"
//   }
// }

As you can see, the built in function doesn't replace the same keys but instead merges them together.

Compared to regular array_merge:

<?php

$array1 = [
    'test' => 'test'
];

$array2 = [
    'test' => 'test2'
];

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

// $result = 
// array(1) {
//   'test' =>
//   string(5) "test2"
// }

The array_merge replaces the values with whatever comes latest but doesn't work for deep array structures.

This library replaces the array_merge_recursive behavior to work like regular array_merge while maintaining the ability to merge deep arrays recursively.

Example:

<?php

use function Rikudou\ArrayMergeRecursive\array_merge_recursive;

$array1 = [
    'test' => 'test'
];

$array2 = [
    'test' => 'test2'
];

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

// $result = 
// array(1) {
//   'test' =>
//   string(5) "test2"
// }

Deeper level array example

These two arrays are used in the following example:

<?php

$array1 = [
    'test' => [
        'key1' => 'test',
        'key2' => 'test',
        'key3' => 'test'
    ]
];

$array2 = [
    'test' => [
        'key2' => 'test2',
        'key4' => 'test2'
    ]
];

Result of built-in array_merge_recursive

array(1) {
  'test' =>
  array(4) {
    'key1' =>
    string(4) "test"
    'key2' =>
    array(2) {
      [0] =>
      string(4) "test"
      [1] =>
      string(5) "test2"
    }
    'key3' =>
    string(4) "test"
    'key4' =>
    string(5) "test2"
  }
}

Here you can see that key2 gets changed to array with both values added.

Result of built-in array_merge

array(1) {
  'test' =>
  array(2) {
    'key2' =>
    string(5) "test2"
    'key4' =>
    string(5) "test2"
  }
}

Since array_merge doesn't work recursively it completely replaces the test key with value from 2nd array.

Result of array_merge_recursive from this library

array(1) {
  'test' =>
  array(4) {
    'key1' =>
    string(4) "test"
    'key2' =>
    string(5) "test2"
    'key3' =>
    string(4) "test"
    'key4' =>
    string(5) "test2"
  }
}

This library correctly replaces the key2 with later value while keeping the whole tree.