Variables in PHP

This page describes documentation valid for PHP 4 and PHP 5.

Basics

Variables in PHP:

1. always begin with a dollar sign ($)
2. start with a letter or underscore (_)
3. may contain any number of letters, numbers, and underscores
4. are case-sensitive

Examples of Acceptable Variable Names

$var
$_var
$_Var
$VAR
$VAR_001

This is not a comprehensive list, merely examples.

Examples of Unacceptable Variable Names

$var*

(Variable names may only contain letters, numbers, and underscores.)

$var #1

(Variable names may not contain # or spaces.)

var$

(Variables names must begin with a dollar sign.)

Assigning Values to Variables

To assign a value to a variable, use a single equal sign (=)

$var = "Hello, world."