Complete PHP Tutorial – Chapter 3

In this tutorial, you’ll learn about PHP Variables, Constants and Parameters.

Regular Variables

Variables are containers which we use for storing information. PHP variables work a bit differently to other languages so I suggest you pay close attention here.

A variable starts with a dollar sign ($) which is then followed by the name of the variable. That is then followed by a = sign and the value is entered after that. After the value you need a semi-colon as usual. Let’s have an example.

PHP Code:

$variable_name = 100;

There are some important things you must remember when setting a variable name:

  • The name of a variable must start with a letter or an underscore.
  • Variable names are case sensitive (so $people would not be the same as $PEOPLE).
  • A variable name cannot start with a number.
  • A variable name can contain only letters, numbers and underscores.

When defining a variable you do not have to tell PHP the data type. This is where it is a bit different to other languages and shares more in common with something like python as PHP looks at what you set the variable too and gives it a datatype based on that.

Because of this, you also never need to declare a variable, it is created the moment you assign a value to it.

You can also use variables in other functions or constructs instead of directly typing in data. This comes in handy when you will be using a value more than once and don’t want to have to retype it and/or when the value of it will be changing often. For example:

PHP Code:

$name = “Yeah Hub”;
//Since I put in the quotation marks PHP knows that is a string.
echo $name;
//Now the echo construct goes and looks for variable $name and outputs it.


A constant is similar to a variable except it is defined once then cannot be undefined or have its value changed. The same rules for making a constant variable name apply here.

To create a constant you use the define() function.

PHP Code:

define(name, value, case-insensitive)


  • name: Specifies the name of the constant.
  • value: Specifies the value of the constant.
  • case-insensitive: Should the constant name be case sensitive? This is defaulted to false.


PHP Code:

define(“HELLO”, “Hello there friend.”);
echo HELLO;

//Outputs “Hello there friend.”

Example using case sensitive:

PHP Code:

define(“HELLO”, “Hello my friend.”, true);
echo hello;

//Outputs “Hello my friend.”

You can also define constants by using the const variable. This works in exactly the same way but is always case-sensitive and is defined a little differently.

PHP Code:

const CONSTANT = value;

Instead of using define, you simple remove the $ from in front of a variable and use the keyword const in front of the variable name.

Continue to Next Chapter – Complete PHP Tutorial – Chapter 4

Credit Goes to Mr. RYDIOO

Have something to say about this article? Comment below or share it with us on Facebook or Twitter.

Step by step hacking tutorials about wireless cracking, kali linux, metasploit, ethical hacking, seo tips and tricks, malware analysis and scanning.



Subscribe to Our Newsletter and Get Instant Delivered to Your Email Inbox.

We respect your privacy and take protecting it seriously.

Leave a Reply

Your email address will not be published. Required fields are marked *