Variables in PHP

This page describes documentation valid for PHP 4.

This page describes documentation valid for PHP 5.

Basics

Variables in PHP:

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

Acceptable Variable Names

$var

$_var

$_Var

$VAR

$VAR_001

This is not a comprehensive list, merely examples.

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."