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.
These functions are available as part of the standard module, which is always available.
There is no installation needed to use these functions, they are part of the PHP core.
This extension does not define any configuration directives.
This extension does not define any resource types.
CASE_UPPER and CASE_LOWER are used with the array_change_key_case() function. They respectively are used for changing a string to upper case or lower case.