How to Append Arrays in PHP While Maintaining Key Integrity and Avoiding Duplicates?

Appending Arrays in PHP: Avoiding Comparison and Maintaining Key Integrity

PHP offers various ways to connect arrays. However, some methods can lead to undesirable results, especially when it comes to maintaining keys and avoiding duplicates. To solve these problems, it is essential to understand the appropriate method.

Join arrays without key comparison

To append one array to another without changing their keys compare, PHP offers the array_merge function. It seamlessly joins elements from multiple arrays while preserving the key of the first array:

<code class="php">$a = array('a', 'b');
$b = array('c', 'd');
$merge = array_merge($a, $b); // Ergebnis: ['a', 'b', 'c', 'd']</code>

In contrast, the operator can be used to join arrays. However, it does not append the elements, but instead overwrites same keys:

<code class="php">$merge = $a + $b; // Ergebnis: ['a', 'b']</code>

Conclusion

array_merge is the preferred method for appending arrays in PHP when it is about maintaining your keys and avoiding duplicates. It is both elegant and efficient and ensures the integrity of the linked data.

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