What is Variable?

Variables are known to hold data that can change during runtime of a program. The following are few important factor about PHP variables
- A PHP variable should declared using a dollar sign followed by variable name.
- A variable name can start with an underscore or with a letter.
- PHP variables are case sensitive .So, $Web  is not the same as $web.

Naming convention

Similar to other programming language such as C and C++, PHP also fallows a naming convention that should be used while declaring variables. Consider the fallowing example

$myVal = "My First Variable";

The above examples shows the naming convention used in PHP to declare a variable:

- The dollar sign: In PHP, each variable that you declared should begin with a dollar sign.

- Variable name: It is always advisable to choose meaningful variable names. Which will help developers to understand why the variable was declared and where it can be used. For example, if you use the variable name $u for User name and $e for User email address then  you may misinterpret it at a latter stage. So, when you start using PHP or any other programming languages  you should use meaningful variable names.

- Operator : The equal sign is an operator that assigns a value to the variables.

- Data type (value assigned to a variable):  The string "My First Variable" is the value that assign to the variable $myVal.

Variables are assigned using values. These value can be of Boolean, integer, float, or string type. Once declared, variables can be referenced in a script.