PHP Variables

In this PHP programming language tutorial we will look at variables. A variable is used to store information or values in, like text-strings, numbers or arrays. As long as you don’t remove the value in a variable then you can use the variable (thus the value) over and over again.

PHP Variable Declaration

All variables in PHP begin with the $ sign. A common mistake of new PHP programmers is to forget the $ sign before a variable, so don’t forget it!
Let’s look at a variable declaration in PHP:
<?php
$sample = 100;
$sample2 = "Hello World!";
?>
First we declare the variables e.g. ($sample is 100  and $sample2 is Hello World ).
Important for using variables, The code must have dollar sign($) in variables when entering a code and equals  when assigning a data e.g. a number or name
Don't forget a semi colon when it ends your variables and then the apostrophe must apply in data for names that should be execute in page.
Note:  for people that have written programs in other language, such as C/C++ for instance, you don’t have to determine the data type of the variable (example in C Language: int my_var = 20; .) The PHP language is a loosely typed language, which means that PHP automatically converts the variable to the correct data type, depending on its value. The C/C++ languages are strongly typed programming languages.

Variable Rules

You have to follow some rules when naming a variable:

• A variable name cannot contain spaces.
• A variable name must start with a letter or an underscore ( _ )
• A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ ).

Reference: codingunit.com