PHP variables can hold numbers or strings of characters. You store information in variables with a single equal sign (=). For instance, the following four PHP statements assign information to variables:

$age = 12;
$price = 2.55;
$number = -2;
$name = "Little Bo Peep";

Notice that the character string is enclosed in quotes, but the numbers are not.

Whenever you put information into a variable that didn’t exist before, you create that variable. For instance, suppose you use the following PHP statement:

$firstname = "George";

If this statement is the first time that you’ve mentioned the variable $firstname, this statement creates the variable and sets it to “George”. If you have a previous statement setting $firstname to “Mary”, this statement changes the value of $firstname to “George”.

You can also remove information from a variable. You might do this in order to clear out information or to initialize the variable. For example, the following statement takes information out of the variable $age:

$age = "";

The variable $age exists but doesn’t contain a value. It doesn’t mean that $age is set to 0 (zero) because 0 is a value. It means that $age doesn’t store any information. It contains a string of length 0.

You can go even further and uncreate the variable by using this statement:


After this statement is executed, the variable $age no longer exists.