PHP Variables

PHP Variables – Complete Beginner Tutorial

Variables are one of the most important concepts in PHP. Almost every PHP program uses variables to store information, perform calculations, display dynamic content, process forms, communicate with databases, and much more.

Without variables, every value would have to be typed manually into your code. Variables make programs flexible, reusable, and much easier to maintain.

What is a Variable?

A variable is simply a named container that stores information.

Think of a variable as a labelled storage box. Instead of remembering the actual value, your program remembers the label.

For example:


$name = "John";

Here:

  • $name is the variable.
  • John is the value stored inside it.

Later in the program you can use $name instead of writing “John” repeatedly.

Creating Variables

Variables in PHP always begin with the dollar sign ($).


<?php

$name = "John";

$city = "London";

$age = 30;

?>

You can now display them:


<?php

echo $name;

echo "<br>";

echo $city;

echo "<br>";

echo $age;

?>

Output:


John

London

30

How Variables Work

Imagine you own a travel company.

Instead of writing your company name hundreds of times, you could write:


$company = "Travel & Culture Services";

Whenever you need the company name:


echo $company;

If your business name changes, you only need to update it in one place.

Variable Naming Rules

PHP has a few simple rules.

Rule Example
Must begin with $ $name
Must start with a letter or underscore $city
Cannot begin with a number $123name ❌
Can contain numbers $name1 ✔
No spaces $first_name ✔
Case Sensitive $name ≠ $Name

Good Variable Names

Always choose meaningful names.

Good examples:


$customerName

$totalPrice

$productName

$emailAddress

$bookingDate

$hotelName

Poor examples:


$a

$b

$x

$temp1

$abc

$data2

Good names make your programs easier to understand months or even years later.

Changing Variable Values

A variable can be updated whenever needed.


<?php

$price = 100;

echo $price;

$price = 150;

echo "<br>";

echo $price;

?>

Output:


100

150

The second assignment replaces the first value.

Displaying Variables Inside Text

PHP can combine variables with normal text.


<?php

$name = "Alice";

echo "Welcome $name";

?>

Output:


Welcome Alice

You can also use curly braces to make complex strings easier to read.


echo "Welcome {$name}";

Multiple Variables

You can create as many variables as your application requires.


<?php

$firstName = "Ali";

$lastName = "Khan";

$country = "Pakistan";

$profession = "Developer";

echo $firstName;

echo "<br>";

echo $lastName;

echo "<br>";

echo $country;

echo "<br>";

echo $profession;

?>

Variables and Mathematics

Variables can store numbers and be used in calculations.


<?php

$price = 120;

$quantity = 4;

$total = $price * $quantity;

echo $total;

?>

Output:


480

Tip:

Variables are not limited to text or numbers. They can also store arrays, objects, dates, files, database records, and much more.

Variable Scope

The scope of a variable determines where it can be accessed within a PHP script.

PHP supports three main types of variable scope:

  • Local Variables
  • Global Variables
  • Static Variables

Local Variables

A variable created inside a function is only available within that function.


<?php

function showName()
{
    $name = "John";
    echo $name;
}

showName();

?>

Output:


John

The variable $name cannot be accessed outside the function.

Global Variables

A variable created outside a function is known as a global variable.


<?php

$company = "Travel & Culture Services";

function displayCompany()
{
    global $company;
    echo $company;
}

displayCompany();

?>

Output:


Travel & Culture Services

The global keyword allows a function to access variables defined outside the function.

Static Variables

Normally, local variables disappear after a function finishes executing.

Static variables remember their values between function calls.


<?php

function counter()
{
    static $count = 0;

    $count++;

    echo $count . "<br>";
}

counter();
counter();
counter();

?>

Output:


1
2
3

This feature is useful when tracking how many times a function has been executed.

Checking if a Variable Exists

PHP provides the isset() function.


<?php

$name = "Ali";

if(isset($name))
{
    echo "Variable exists";
}

?>

Output:


Variable exists

Checking for Empty Variables

The empty() function checks whether a variable contains a value.


<?php

$name = "";

if(empty($name))
{
    echo "Name is empty";
}

?>

Output:


Name is empty

Removing Variables

You can remove a variable using unset().


<?php

$name = "John";

unset($name);

?>

After calling unset(), the variable no longer exists.

Variable Variables

PHP supports a unique feature called variable variables.


<?php

$country = "Pakistan";

$Pakistan = "Beautiful Country";

echo $$country;

?>

Output:


Beautiful Country

This feature is powerful but should be used carefully because it can make code difficult to understand.

Type Juggling

PHP automatically converts data types when appropriate.


<?php

$number = "100";

$total = $number + 50;

echo $total;

?>

Output:


150

PHP automatically converts the string into a number.

Real World Example – Tour Booking System

Variables become extremely useful when building real applications.


<?php

$tourName = "Hunza Valley Tour";

$price = 950;

$days = 7;

echo "<h2>$tourName</h2>";

echo "<p>Duration: $days Days</p>";

echo "<p>Price: USD $price</p>";

?>

Output:


Hunza Valley Tour

Duration: 7 Days

Price: USD 950

Imagine managing hundreds of tours. Instead of manually editing every page, variables allow information to be generated dynamically from a database.

Common Beginner Mistakes

Mistake Correct Version
name = “John”; $name = “John”;
$123name $name123
$Name and $name assumed equal Variables are case-sensitive
Using undefined variables Check using isset()

Best Practices

  • Use meaningful variable names.
  • Keep naming consistent.
  • Avoid single-letter variable names.
  • Use camelCase or snake_case consistently.
  • Initialize variables before using them.
  • Check variables with isset() when necessary.
  • Use comments when variable purpose is unclear.

Practice Exercises

  1. Create variables for your name, city and country.
  2. Display them using echo.
  3. Create two numeric variables and calculate their sum.
  4. Use isset() to verify a variable exists.
  5. Use empty() to check an empty variable.
  6. Create a simple tour package using variables.

Summary

Variables are the foundation of PHP programming. They allow you to store, manipulate and display data efficiently. Every PHP application, from a simple contact form to a large e-commerce website, depends heavily on variables.

You learned how to create variables, follow naming rules, update values, perform calculations, work with scope, check variable existence and apply variables in real-world situations.

Mastering variables is essential because nearly every future PHP topic builds upon this knowledge.

Frequently Asked Questions

Do all PHP variables start with $?

Yes. Every variable name in PHP begins with the dollar sign.

Are variable names case-sensitive?

Yes. $name and $Name are considered different variables.

Can variables store numbers and text?

Yes. Variables can store strings, integers, decimals, arrays, objects and many other data types.

What does isset() do?

It checks whether a variable exists and contains a value.

What does unset() do?

It removes a variable from memory.

Quick Challenge

Create a PHP page displaying information about a hotel package.

Store the following information in variables:

  • Hotel Name
  • City
  • Price Per Night
  • Number of Rooms
  • Total Cost

Display the information using HTML generated by PHP.

Next Tutorial

Now that you understand variables, it is time to learn about the different types of data that variables can hold.

Next: PHP Data Types

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