In this chapter, we're going to be looking at PHP arrays. PHP arrays are implemented as an ordered map that associates values to keys. There are three types of array in PHP: indexed, associative, and multidimensional.
PHP has a lot of array functions that cover a great many common uses for functions. Before you write a function to operate on an array, you should first check if there is already one. They are implemented in C and so are going to be a lot faster than any function you could write in PHP to achieve the same result. The array manual page
1 lists them in one place, and you should ...