PHP Variables

In PHP, a variable is declared using a $ sign followed by the variable name. Here, some important points to know about variables:

  • As PHP is a loosely typed language, so we do not need to declare the data types of the variables. It automatically analyzes the values and makes conversions to its correct datatype.
  • After declaring a variable, it can be reused throughout the code.
  • Assignment Operator (=) is used to assign the value to a variable.

Syntax of declaring a variable in PHP is given below:


Rules for declaring PHP variable:

  • A variable must start with a dollar ($) sign, followed by the variable name.
  • It can only contain alpha-numeric character and underscore (A-z, 0-9, _).
  • A variable name must start with a letter or underscore (_) character.
  • A PHP variable name cannot contain spaces.
  • One thing to be kept in mind that the variable name cannot start with a number or special symbols.
  • PHP variables are case-sensitive, so $name and $NAME both are treated as different variable.

PHP Variable: Declaring string, integer, and float

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


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

PHP Variable: Sum of two variables



PHP Variable: case sensitive

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


My car is red

Notice: Undefined variable: COLOR in C:\xampp\htdocs\dkyadav\index.php on line 11
My book is

Notice: Undefined variable: coLOR in C:\xampp\htdocs\dkyadav\index.php on line 12
My shirt is

PHP Variable: Rules

  • PHP variables must start with letter or underscore only.
  • PHP variable can’t be start with numbers and special symbols.
  1. $a=“hello”;//letter (valid)
  2. $_b=“hello”;//underscore (valid)
  3. $4c=“hello”;//number (invalid)
  4. $*d=“hello”;//special symbol (invalid)


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Hello, I am Dharmendra Yadav and I am a Python Developer with experience in web development using Django, Flask, REST API, SQL, MySQL, HTML, CSS, JavaScript, WordPress, Oracle Cloud, AWS and Git. I also write technical articles where I explain web development and Software Engineering. Facebook , Linkedin

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