Variables
In PHP, variables are represented by a dollar sign $ followed by a case-sensitive name. Values are assigned to a variable using the = operator.
<?php
$name = 'Ryan';
Variables names must start with either an alphabetic character or an underscore.
<?php
$name; // This is allowed.
$Name; // This is allowed.
$_name; // This is allowed.
$1; // This is not allowed.
You can declare multiple variables at once by using the = operator multiple times.
<?php
$a = $b = 100;
You can then use a variable by referencing it in the same way as your declared it.
<?php
$message = 'Hello, world';
echo $message;