PHP Variable

Updated: April 5th, 2022, 06:14:45 IST
Published: March 29th, 2022
PHP Variable
Title: PHP Variable

PHP variable is a "container" that stores value and information. A variable starts with the $ sign, followed by the name of the variable.

PHP Variables: Basics

Variable names follow the same rules as other labels in PHP. A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores.

A variable can have a short name (like x and y or a and b) or a more descriptive name (name, age, description, multiple_hobbies).

As a regular expression, it would be expressed thus: ^[a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*$

Note: A letter here is a-z, A-Z, and the bytes from 128 through 255 (0x80-0xff).

  • A variable starts with the $ sign, followed by the name of the variable.
  • A variable name must start with a letter or the underscore character.
  • A variable name cannot start with a number.
  • A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ ).
  • The variable name is case-sensitive. ($age and $AGE are two different variables)

PHP variable:

Think of variables something like containers that can store any value.

PHP Code:


PHP Variable Examples

PHP Variable Examples


PHP Variable Output

PHP Variable Output


Code: php-variable.php

$welcome_text = " PHP Tutorial";
$x = 5;
$y = 10.5;
$name = 'Sagar';
$Name = 'Kalyan';

echo "Welcome to " . $welcome_text . "! - ";     
// outputs "Welcome to PHP Tutorial!";
echo $x + $y . " - ";      
// outputs "15.5"
echo "$x + $y" . " - ";      
// outputs "5 + 10.5"
echo "$name, $Name" . " ";      
// outputs "Sagar, Kalyan"

PHP is a Loosely Typed Language

In the example above, did you notice that we did not specified PHP variable which data type the variable is.

PHP automatically associates a data type to the variable, depending on its value.

In PHP 7, type declarations were added. This gives an option to specify the data type expected when declaring a function, and by enabling the strict requirement, it will throw a "Fatal Error" on a type mismatch.

You will learn more about strict and non-strict requirements, and data type declarations in the PHP Functions chapter.