PHP and MySQL® Web Development, Fifth Edition

3. Using Arrays

This chapter shows you how to use an important programming construct: arrays. The variables used in the previous chapters were scalar variables, which store a single value. An array is a variable that stores a set or sequence of values. One array can have many elements, and each element can hold a single value, such as text or numbers, or another array. An array containing other arrays is known as a multidimensional array.

PHP supports arrays with both numerical and string indexes. You are probably familiar with numerically indexed arrays if you’ve used any other programming language, but you might not have seen arrays using string indexes before, although you may have seen similar things called hashes, maps, or dictionaries elsewhere. ...