When duplicating arrays in PHP, it’s crucial to understand the difference between copying by value and copying by reference. If you want to ensure that changes to the new array do not affect the original, you’ll need to create a copy that is independent of the original. The most straightforward way to accomplish this is through the use of the `array_merge()` function, which can create a new array. However, be cautious when handling multi-dimensional arrays, as this method may not perform a deep copy; it can still reference the sub-arrays. If you’re dealing with a multi-dimensional structure and need to ensure complete independence, using a loop to iterate over each element and create a new array is often the safest approach. Although it might seem less efficient for large arrays, using `array_map()` in conjunction with a callback can be another efficient and elegant solution that allows for duplication while preserving both value types and structure.

One important consideration is to keep in mind is that PHP 7 and later versions have improved performance and memory handling, so using functions like `array_slice()` for shallow copying may that limit some unexpected behaviors, but it’s generally not recommended for creating a standalone duplicate. An example of using a loop would look like this:

$originalArray = [1, 2, 3, 4, 5];
$newArray = [];
foreach ($originalArray as $value) {
    $newArray[] = $value;
}

This method ensures that $newArray is a completely new array without any references to the original array elements. Ultimately, your method choice might depend on your specific use case, particularly if you value performance or need to ensure isolation from the original data.