Arrays are very flexible and powerful data structures. We often encounter a scenario where we need to replace a part of an array with the contents of another array. Although PHP does not provide a specialized method for "local replacement", we can easily achieve this requirement by combining array_slice and array_merge.

array_merge is a commonly used function that combines two or more numbers into a new array. However, when using array_merge, we sometimes encounter some problems, especially when used in init functions. This article will explain how to avoid these errors and provide some solutions.