What is a variable?

According to the meaning of the word, you should suspect it is something which changes all the time. Indeed the main feature of a variable is to be able to change its value. But strictly speaking, what does it mean?

A variable is a small piece of information stored in the memory temporarily. It has a short life cycle. In PHP a variable exists during the generation process of the page. Once the page has been generated, all variables are removed from the memory because they are of no use anymore. A variable is therefore not a file stored on the hard drive but a temporary piece of informaton.
Creating a variable is up to you, that is, you create it when you think it is needed.
What you should know is that a variable is made up of 2 things:

• Its name : in order to identify your variable you must name it. For instance "age_of_visitor"
• Its value : the value is the information conveyed. It can change. For example "17 years".

In this example, I used a variable called "age_of_visitor" with the value "17". The value of a variable can be changed at will and used for any calculations. And when we need it, we call it (by its name) and it tells us what it's set to. It goes on like this: - Hey ! you age_of_visitor variable, what are you set at?
- 17.
- Thanks ! Variables may seem confusing for now but they will be mandatory for your PHP site. For instance, storing a username ("m@teo21") in a name_of_visitor variable, you will be able to use this information to display a personal welcome message like, " Hi m@teo21! welcome". You remember how to display a text in PHP, don't you? The "echo" function you learned in the previous chapter will be very useful for practice!