PHP and MySQL for Dynamic Web Sites: Visual Quickpro Guide, Second Edition

What Are Arrays?

The final variable type I’ll introduce in this book is the array. Unlike strings and numbers (which are scalar variables, meaning they can store only a single value at a time), an array can hold multiple, separate pieces of information. An array is therefore like a list of values, each value being a string or a number or even another array.

Arrays are structured as a series of key-value pairs, where one pair is an item or element of that array. For each item in the list, there is a key (or index) associated with it. The resulting structure is not unlike a spreadsheet or database table (Table 2.2).

Table 2.2. The $artists array uses numbers for its keys.

Array Example 1: $artists
Key	Value
0	Low
1	Aimee Mann
2	Ani DiFranco
3	Spiritualized ...