How is array_slice used in PHP?

The array_slice() function is used to extract a portion of values from an array based on certain conditions and returns a new array.

The syntax of this function is as follows: array_slice(array, start, length, preserve).

Explanation of parameters:

1. Essential, the original array.
2. It is required to specify the index position to start the extraction. When the index is a positive number, the extraction begins from the front; if it is a negative number, the extraction starts from the end.
3. Optional parameter specifying the length of the substring to be extracted. Positive numbers indicate the number of elements to return, while negative numbers indicate the number of elements counting from the end. If not set, all elements from the starting position to the end of the array will be returned.
4. Preserve: Optional parameter that specifies whether to keep the original keys of the array. If set to true, the keys will be preserved; if set to false, the keys will be reset. Default is false.

The function returns a new array containing the extracted elements.