These functions allow you to interact with and manipulate arrays in various ways. Arrays are essential for storing, managing, and operating on sets of variables.
Simple and multi-dimensional arrays are supported, and may be either user created or created by another function. There are specific database handling functions for populating arrays from database queries, and several functions return arrays.
Please see the Arrays section of the manual for a detailed explanation of how arrays are implemented and used in PHP.
The constants below are always available as part of the PHP core.