deadserious

This is a simple introduction tutorial to help you get started as well as give you some ideas on what you can do with PHP. PHP is a server side html embedded scripting language that can be used to create dynmaic web pages and many other things. Some benefits of using PHP are it's free, it's fast, it's fairly easy to learn, and you can embed it into your regular html pages.

To use PHP you'll need to have access to a web server with PHP installed on it. Most Web Hosts offer PHP support. You can also install PHP and run it on your own system which can make it easier to learn and test PHP scripts. CLICK HERE for a tutorial on setting up PHP to run on your own computer.

Okay we'll begin with a simple PHP script for an example.
1. Copy that code into your favirote text editor, note pad will work just fine. Save it as test.php. Make sure it ends with a .php extension. Upload it to where you store your web accessible files and call it up in your browser. If you see "PHP is easy!" then you know PHP is installed and working on your server. Notice the <?php and the ?> these are the start and end tags, they say hey parse up some PHP and hey stop parsing now. You can just use <? for the start tag if the short tag is enabled on your server. Also notice the semicolon at the end of the echo statement. This tells the parser where one line of code ends and the next one begins. You could do this just as easily with regular html, but we needed an example to show you how it works right?
If you look at the source code for that page it will look like this:
You can't view the sever side scripts source code from your browser. It will be removed by the time it gets to your browser for viewing. The only code you'll be able to see is the regular html that was included in the script and/or generated by it.

PHP Comments
Comments are used for helping the user and/or the developer remember and understand what the program does and/or provide instructions. You can use single or multiline comments. Comments will be stripped out of the program and ignored by the interpreter.
Example:
PHP Variables.
You can define a variable to store for later use. Variables start with the $ sign and are assigned with the = operator . To use a variable you need to assign a value to it.

$snowboarding = 'fun';

The name of the variable is on the left of the = sign and the value is on the right. In this case $snowboarding has the value of fun. Variables can contain numbers, letters, and underscores, but may not begin with a number.

Some examples of using variables.
The output of this code would be:
Snowboarding is really fun and sometimes painful

echo prints the output to the browser. You can also use print, but there is slight difference between the two. Also notice how you can jump in and out of PHP mode when ever you wish, and how the variable contains it's value through out the script, but only when you are in PHP mode. Okay so now you get the idea of mixing PHP in with HTML.

More examples of using variables.
The out put of this code would be the same as above:
Snowboarding is really fun and sometimes painful

If you are just echoing a variable you don't need to surround it with quotes.

The difference betweeen single and double quotes

If you want to print out the value of a variable within a string you need to surround the string with double quotes otherwise the actual variable name will be printed out.

<?php
$name = 'Web';
$lastname = 'Design';
echo "My first name is $name and my last name is $lastname";
?>
The output of this would be:
My first name is Web and my last name is Design

If we do the same with single quotes:
<?php
$name = 'Web';
$lastname = 'Design';
echo 'My first name is $name and my last name is $lastname';
?>
The output would be:
My first name is $name and my last name is $lastname

The same thing is true when assigning variables.
<?php
$name = 'Web';
$lastname = 'Design';
$fullname = "My first name is $name and my lastname is $lastname";
echo $fullname;
?>
The output would be:
My first name is Web and my last name is Design

If we assign the vaules to $fullname with single quotes:
<?php
$name = 'Web';
$lastname = 'Design';
$fullname = 'My first name is $name and my lastname is $lastname';
echo $fullname;
?>
The output would be:
My first name is $name and my last name is $lastname

In summary variables aren't replaced with their value unless they are surrounded by double quotes with a few exceptions.

Using Basic Operatros

Comparison operators compare two values.
== is equal to
!= is not equal to
< is less than
> is greater than
<= is less than or equal to
>= is greater than or equal to

Arithmetic Operators
Just like on a calculator.
+ Addition
- Subtraction
* Multiplication
/ Division

Logical Opertators
&& and (The first and the second is true)
|| or (The first or the second is true)

Some basic math.
<?php
$monthly = 10;
$yearly = 20;
$total=$monthly+$yearly;
echo $total;
?>
The output would be 30.

<?php
echo 2+2;
?>
The out put would be 4.

<?php
$monthly = 10;
$yearly = 20;
$monthly+=10; //Same as $monthly=$monthly+10;
$yearly+=10;
$total=$monthly+$yearly;
echo $total;
?>
The out put would be 50.

<?php
$monthly =10;
$monthly++; //Adds one to monthly. The same as $monthly=$monthly+1;
echo $monthly;
?>
The output would be 11.

The same would work with - and --

Note: ++ and -- are Incrementing/Decrementing Operators and += is an Assignment Operator just like the = sign.

Easy enough right?

Yes it's that easy. For the basics anyways.


String Operators.
. concatenate (put two strings together) Returns the concatenation of its right and left arguments.
.= (concatenate and assign) Appends the argument on the right side to the argument on the left side.

<?php
$name = "Web";
$fullname = $name . "Design";
echo $fullname;
?>
Now $fullname contains WebDesign. The . is used to put two strings together.
The output of this would be WebDesign

If we wanted to put a space in there we could do it like this:
<?php
$name ="Web";
$fullname = $name ." " ."Design";
echo $fullname;
?>
Now the output would be Web Design. To make it even easier we could write the variable like $name = "Web "; so that the space is already there.
<?php
$name = "Web ";
$name .= "Design";
echo $name;
?>
Now $name would contain Web Design. So the output would be Web Design.

PHP Control Structures
Using if, elseif, and else, to check for certain conditions.

Examples:
<?php
$howmuch = 10;
if ($howmuch == 10) {
????: NamePros.com http://www.namepros.com/showthread.php?t=14637
print 'how much is 10';
}
?>
This checks to see if the variable $howmuch is equal to 10. If it is it goes on and executes the code between the curly braces. In this case the result would be how much is 10.

Sometimes you may want to make the script do something if the if condition is not true.
<?php
$howmuch = 5;
if ($howmuch >= 10) {
print 'how much is 10 or greater';
} else {
print 'how much is not enough';
}
?>
This checks to see if the variable $howmuch is greater than or equal to 10 and if it is then it prints how much is 10 or greater. If $howmuch is not greater than or equal to 10 then it bypasses the code in in the first set of curly braces and executes the code within the else statements curly braces. In this case the result would be how much is not enough.


You can also check for mutltiple conditions with elseif.
<?php
$howmuch = 10;
if ($howmuch <= 7) {
print 'how much is less than or equal to 7';
} elseif ($howmuch == 6) {
print 'how much is 6';
} else {
print "how much is actually $howmuch";
}
?>
Scince $howmuch is not less then or equal to 7 and it doesn't equal 6 the result would be how much is actually 10.

Now you get it right? You can add as many elseif statements as you need. You use the else statement for when all else fails.

Using Switch

First an example of an if elseif statement.
<?php
if ($day == 'Monday') {
echo 'Monday';
} elseif ($day == 'Thursday') {
echo 'Thursday';
} else {
echo 'Not today';
}
?>

Now we can get the same results using switch.
<?php
switch ($day)
{
case "Monday":
echo 'Monday';
break;
case "Thursday":
echo 'Thursday';
break;
default:
echo 'Not today';
break;
}
?>
You can use switch as an alternative for if elseif statements. It's good to use switch when you're checking for alot of conditions rather than having huge elseif statements.

deadserious

Including Files
You can also add PHP to your HTML pages by including files.
For example a file called header.inc contatins:
<html>
<head>
????: NamePros.com http://www.namepros.com/showthread.php?t=14637
<title>Title of your page</title>
</head>
<body>
<h7>Header Text</h7>

and your main page named index.php contains:
All of your usual html content here.

And a file called footer.inc contains:
Coypright yoursite, All Rights Reserved. and what ever else you want in your footer here.

Okay so now we've got three files: header.inc, index.php, and footer.inc

Putting it all together.
In your index.php you include the header.inc and footer.inc files like this:

File index.php
<?php
include("header.inc");
?>
All of your main html content here.
<?php
include("footer.inc");
?>
</body>
</html>

Now with the examples above the source code would like this:
<html>
<head>
<title>Title of your page</title>
</head>
<body>
<h7>Header Text</h7>
All of your usual html content here.
Coypright yoursite, All Rights Reserved. and what ever else you want in your footer here.
</body>
</html>

You get it now right?

More info on including files in an upcoming tutorial. Stay tuned!

Alright that's all for now. I'll add on to this tutorial in the coming days, weeks, and months. Some things to come will be Getting data from forms, using loops, and a bit more. Feel free to point out any mistakes I've made or ask any questions.

Keith[imported]

I'd suggest changing the if elseif statement around slightly.

Instead of using you should use This way, if you accidentally use one = sign instead of two, you won't replace the value of the variable and PHP will throw up an error message.

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deadserious

Hey nice suggestion! That's a good way to check if you've used one = sign where you should have used two.

If you were only to use one though, you would usually find something wrong becasue you wouldn't get the results you expect in the testing process of your script, but the way you suggested would probably help you solve the problem alot faster.
????: NamePros.com http://www.namepros.com/showthread.php?t=14637

I wonder though is there a difference between the two?

$day == 'Monday' and 'Monday' == $day

Could that cause problems in certain situations or would using either method produce the same results in any situation?

Anyways nice tip!

Keith[imported]

It should work fine under any circumstance. If you use that method and you do accidentally use the one = sign, you will get a parse error for that line, which makes it soo much easier to debug.

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DarkDevil

in vb the order of which the variables are listed are very important.. but i think in php it doesn't matter so much. But i like having the variable first, dunno why

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deadserious

I'm used to using the variable first and I've never had a problem with entering one = sign when I should have two. I can see how you could though, especially when your just beginning. It kind of seems backwards to me if you do it the opposite, but I learned Perl before PHP so the two == signs was already a habbit for me for the most part. Although in Perl you usually compare strings with eq instead of ==

happyyo

Thanks guys !!! I find your tutorials really useful.

Laura

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deadserious

You're Welcome! Thanks for your comments.

Sohil

Very nice tutorial deadserious!

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Cjpixel

uuuh, this is my first time to encounter PHP, I am just trying to learn this just now, so I just want to ask more questions.

Now, you stated that there are comments to help the user remember, will that always appear when you're using notepad?
Moreover, is it always before the body tag?

I hope you can give me an insight about this Deadserious. Thanks.

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emeri

I like your tutorial

matrics

nice tutorial, was very useful for me

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chaos_theory

thanks for sharing

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Petter

Very nice tut! I've wanted to learn PHP for long and now i have desided i will!

Thanks for the share!

Petter

snoopi

Looking forward the more advanced tutorial Nice job

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majinbuu1023

thanks...are there anymore tutorials coming..
btw WOOOOT I did something in php http://kwacker.com/php/test.php

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ammo

very informative, keep them coming!

unknowngiver

Nice tutorial
Thanks for shairing...lookin forword for more tutorials from u

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Element

Thanks for the great tutorial Deadserious! I found this very useful when I first started php which wasnt long ago.

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myengines

great articles, its usefull for me!

krazyvan05

That is a great tutorial. I have a question tho. I have learned java, it seems very similar to PHP. What is the difference between these two codings.

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deadserious

PHP is more of procedural and/or somewhat Object Oriented language and Java is an Object Oriented language. PHP is also an interpreted language and Java is a complied language, although in some cases it could be considered interpreted such as when using servlets. They are a lot a like in a lot of ways though, since PHP takes so much from Java.

coolpix

Splendid tutorial! Thanks for sharing!

se

thanx for sharing

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