PHP Operators

Filed Under: Learn PHP, PHP Introduction, PHP Operators, PHP String Variables, PHP Strlen Strpos, PHP Syntax, PHP Tutorials, PHP Variables

Operators are used to operate on values.

PHP Operators

This Section lists the different operators used in PHP.

Arithmetic Operators

Operator	Description	Example	Result
+	Addition	x=2 x+2	4
-	Subtraction	x=2 5-x	3
*	Multiplication	x=4 x*5	20
/	Division	15/5 5/2	3 2.5
%	Modulus (division remainder)	5%2 10%8 10%2	1 2 0
++	Increment	x=5 x++	x=6
--	Decrement	x=5 x--	x=4

Assignment Operators

Operator	Example	Is The Same As
=	x=y	x=y
+=	x+=y	x=x+y
-=	x-=y	x=x-y
*=	x*=y	x=x*y
/=	x/=y	x=x/y
.=	x.=y	x=x.y
%=	x%=y	x=x%y

Comparison Operators

Operator	Description	Example
==	is equal to	5==8 returns false
!=	is not equal	5!=8 returns true
<>	is not equal	5<>8 returns true
>	is greater than	5>8 returns false
<	is less than	5<8 returns true
>=	is greater than or equal to	5>=8 returns false
<=	is less than or equal to	5<=8 returns true

Logical Operators

Operator	Description	Example
&&	and	x=6 y=3 (x < 10 && y > 1) returns true
\|\|	or	x=6 y=3 (x==5 \|\| y==5) returns false
!	not	x=6 y=3 !(x==y) returns true

PHP String

Filed Under: Learn PHP, PHP Introduction, PHP String Variables, PHP Syntax, PHP Tutorials, PHP Variables

PHP String Variables

A string variable is used to store and manipulate text.

String Variables in PHP

String variables are used for values that contain characters.

In this chapter we are going to look at the most common functions and operators used to manipulate strings in PHP.

After we create a string we can manipulate it. A string can be used directly in a function or it can be stored in a variable.

Below, the PHP script assigns the text "Hello World" to a string variable called $txt:

PHP code

$txt="Hello World";
echo $txt;

The output of the code above will be:

OUTPUT
Hello World

Now, lets try to use some different functions and operators to manipulate the string.

The Concatenation Operator

There is only one string operator in PHP.

The concatenation operator (.) is used to put two string values together.

To concatenate two string variables together, use the concatenation operator:

<?php

$txt1="Hello World!";

$txt2="What a nice day!";

echo $txt1 . " " . $txt2;

If we look at the code above you see that we used the concatenation operator two times. This is because we had to insert a third string (a space character), to separate the two strings.

PHP Variables

Filed Under: Learn PHP, PHP Introduction, PHP Syntax, PHP Tutorials, PHP Variables

PHP Variables

A variable is used to store information.

Variables in PHP

Variables are used for storing values, like text strings, numbers or arrays.

When a variable is declared, it can be used over and over again in your script.

All variables in PHP start with a $ sign symbol.

The correct way of declaring a variable in PHP:

PHP Code

$var_name = value;

New PHP programmers often forget the $ sign at the beginning of the variable. In that case it will not work.

Let try creating a variable containing a string, and a variable containing a number:

PHP is a Loosely Typed Language

In PHP, a variable does not need to be declared before adding a value to it.

In the example above, you see that you do not have to tell PHP which data type the variable is.

PHP automatically converts the variable to the correct data type, depending on its value.

In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it.

In PHP, the variable is declared automatically when you use it.

Naming Rules for Variables

A variable name must start with a letter or an underscore "_"
A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ )
A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)

PHP Syntax

Filed Under: Learn PHP, PHP Introduction, PHP Syntax, PHP Tutorials

PHP Syntax

PHP code is executed on the server, and the plain HTML result is sent to the browser.

Basic PHP Syntax

On servers with shorthand support enabled you can start a scripting block with .

For maximum compatibility, we recommend that you use the standard form

A PHP file normally contains HTML tags, just like an HTML file, and some PHP scripting code.

Below, we have an example of a simple PHP script which sends the text "Hello World" to the browser:

Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another.

There are two basic statements to output text with PHP: Echo and Print. In the example above we have used the echo statement to output the text "Hello World".

Note: The File must have a .php extension. If the file has a .html extension, the PHP code will not be executed.

<?php

echo "Hello World";

PHP Introduction

Filed Under: Learn PHP, PHP Introduction, PHP Tutorials

PHP is a server-side scripting language.

What You Should Already Know

Before you continue you should have a basic understanding of the following:

HTML/XHTML
JavaScript

If you want to study these subjects first, find the tutorials on our Home page .

What is PHP?

PHP stands for PHP: Hypertext Preprocessor
PHP is a server-side scripting language, like ASP
PHP scripts are executed on the server
PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.)
PHP is an open source software
PHP is free to download and use