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Variables and Data Types

 

Introduction

Variables in PHP are used to store data that can be used and manipulated throughout your script. PHP is a loosely typed language, which means you do not need to declare the type of a variable explicitly. The data type is determined automatically based on the value assigned.

Variables

A variable in PHP always starts with a dollar sign $ followed by the variable name. Variable names are case-sensitive and must start with a letter or underscore.

Example:

<?php

$name = "Alice";

$age = 25;

$isAdmin = true;

?>

Data Types

PHP supports several data types. The most common ones include:

String – Represents text.

<?php

$greeting = "Hello, World!";

?>

Integer – Whole numbers without decimals.

<?php

$year = 2025;

?>

Float (or Double) – Numbers with decimals.

<?php

$price = 19.99;

?>

Boolean – Represents true or false.

<?php

$isLoggedIn = true;

?>

Array – Stores multiple values in a single variable.

<?php

$colors = ["Red", "Green", "Blue"];

?>

Object – Represents an instance of a class.

<?php

$date = new DateTime();

?>

Null – Represents a variable with no value.

<?php

$middleName = null;

?>

Dynamic Typing

Since PHP is loosely typed, you can change the type of a variable by assigning a new value of a different type:

<?php

$var = 10;       // integer

$var = "Ten";    // now a string

?>

 

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