Sams Teach Yourself PHP, MySQL® and Apache All in One

Variables

A variable is a special container that you can define, which will then “hold” a value, such as a number, string, object, array, or a Boolean. Variables are fundamental to programming. Without variables, we would be forced to hard-code all the values in our scripts. By adding two numbers together and printing the result, you can achieve something useful:

echo (2 + 4);

This snippet of code will only be useful for people who want to know the sum of 2 and 4, however. To get past this, you could write a script for finding the sum of another set of numbers, say 3 and 5. However, this approach to programming is clearly absurd, and this is where variables come into play.

Variables allow us to create templates for operations (adding two numbers, ...