PHP Variables

A variable in PHP is a name of memory location that holds data. A variable is a temporary storage that is used to store data temporarily.

In PHP, a variable is declared using $ sign followed by variable name.

Syntax of declaring a variable in PHP is given below:

PHP Variable: Declaring string, integer and float

Let's see the example to store string, integer and float values in PHP variables.

Output:

string is: hello string
integer is: 200
float is: 44.6 

PHP Variable: Sum of two variables

Output:

11

PHP Variable: case sensitive

In PHP, variable names are case sensitive. So variable name "color" is different from Color, COLOR, COLor etc.

Output:

My car is red
Notice: Undefined variable: COLOR in C:\wamp\www\variable.php on line 4
My house is 
Notice: Undefined variable: coLOR in C:\wamp\www\variable.php on line 5
My boat is 

PHP Variable: Rules

PHP variables must start with letter or underscore only.

PHP variable can't be start with numbers and special symbols.

Output:

hello 
hello

Output:

Parse error: syntax error, unexpected '4' (T_LNUMBER), expecting variable (T_VARIABLE)
 or '$' in C:\wamp\www\variableinvalid.php on line 2

PHP: Loosely typed language

PHP is a loosely typed language, it means PHP automatically converts the variable to its correct data type.