Learning PHP for the first time

[harmor]

When you're learning a programming language you may become overwelmed with the complexity.
I was very overwelmed when I started to learn PHP for the first time over a year ago.
After I grasped how the syntax worked I could learn new methods more easily.

In this article I'll be giving you tutorials on PHP.
Inorder for you to run the PHP scripts you must have a host that supports PHP (atleast 4.1.0).
If you need hosting you can go to Xen Web Hosting and recieve hosting there.
I highly recommend Crimson Editor for a PHP editor

-- Writing your first PHP program --
Any file that contains PHP must have the extension .php (eg. test.php)
Open Crimson Editor and start a new document (Ctrl + n).

The first thing I'll show you is how to output text using "echo".
To output (or print) text to the browser you can use several statements.
In this article I'll be using the "echo" statement.
Outputting text using PHP is pointless in my opinion but beginners need to start somewhere.

PHP Code:

<?php
echo "This is a string";
?>

The word "echo" tells PHP to output the text between the two quotes to the screen.
The semicolon tells PHP to end the statement (in this case the "echo" statement)
I recommend that you write more "echo" statements to familiarize yourself with the syntax.

I've seen scripts where the coder repeatively uses the "echo" statement for a block of text.
To give you an idea of what I mean imagine copying the "echo" statement and pasting multiple instances of it.
Doing that is unneccesary. In my opinion it makes the code look sloppy.
The way to output a block of text is presented below

PHP Code:

<?php
echo "Hello, my name is Andrew Harmor
I'm 20 years old and I'm attending Waynesburg College
located in Pennsylvania";
?>

-- Variables --
Variables are going to be your friend because you'll be using them a lot.
The naming convention of a variable consists of the dollar sign and almost any name (eg. $header)
A variable cannot start with a number and it cannot have a special character anywhere in the variable name.

PHP Code:

<?php
$name = "Andrew Harmor";
echo $name;
?>

The equals sign assigns the string to the variable. So when you "echo" (output) the variable it'll display
the string that is assigned to that variable.
You may have noticed that the "echo" statement does not contain any quotes.
When dealing with variables encasing them in quotes is not needed.
If you were to output a string with the variable then you'll need to use quotes

PHP Code:

<?php
$name = "Andrew Harmor";
echo "Hello $name";
?>

As you can see variables and the echo statement are pretty much the same.
You can also assign variables to variables.
That may sound confusing but it works the same way as done in the echo statement.

PHP Code:

<?php
$age = "20";
$name = "Andrew Harmor, $age" 
echo $name;
?>

The variable $age has the value "20" assigned to it.
The variable $name has the value "Andrew Harmor, 20" assigned to it.
So when you output the value of $name you'll see exactly that.

If you want to output the value of $age and $name by themselves you would do...

PHP Code:

<?php
$age = "20";
$name = "Andrew Harmor" 
echo "My name is $name, I'm $age years old";
?>

Having a value respective to the variable name gives you greater control over how you output them.
There are some instances where you have to assign variable(s) to another variable but only do so if it's your only option.

[olti]

Thank you, harmor.

[Infamous Flame]

I didn't read the whole thing lol, but wouldn't echoing:

"My name is $name, I'm $age years old"

Simply output exactly that? (My name is $name, I'm $age years old)

You'd have to use concatenation to make it work properly?

I could be wrong though.

[Danny.VBT]

Quote:

Originally Posted by Infamous Flame I didn't read the whole thing lol, but wouldn't echoing: "My name is $name, I'm $age years old" Simply output exactly that? (My name is $name, I'm $age years old) You'd have to use concatenation to make it work properly? I could be wrong though.

Nope - php parses variables inside double strings. Im some stricter languages you would have to concatenate the variable.

[ShadeSlayer]

Also, I can offer some PHP help:

PHP Code:

<?
   include("databaseconnecter.php");
   $navigation[] = array("name" => "Blah",
                                "url"  => $PHP_SELF);

// In this PHP code, it does nothing until you make the other files. But this could be a default layout for your pages.

$output= "Why Halo Thar\n"
            ."What is up with /you\n"

     global $userdata;
     $replace[] = array("/you", "".$userdata[displayname]."");
if(checkAccess("accessadmin"))
{
$output= "<A HREF='edit$PHP_SELF'>Edit This File</A>\n"
}
else
{
$output= "<B>This part is for admins only</B>\n"

   $pagecontents = $output;
   include("main.css");
   include("layout.php");
?>

BTW, that is for people who know PHP and MySQL and such. I doubt a beginner will know what it does, and I doubt it does anything unless you, ofcourse have the right files

[nitr021]

Can I also add that if you are looking for performance the script example provided in this tutorial can take up a few milliseconds to load as it is using ""

try using single quotes like this:

<?php

$age = '20'; 
$name = 'Andrew Harmor, '.$age;  
echo $name; 
?>

I also would like to say that the best place to start php is at php.net
it has a manual. Depending on what you do, just search it and you'll find something.

[Pyrix]

I found that one of the best ways to learn was to start looking at other people's code. I took over a custom written website from a friend, and basically rewrote the whole thing using his code as a basis.

I knew the very basics, but because i knew roughly how computers worked logically, and the fact that, for example, 60 queries on a page was bad, i knew what needed to be changed, and all i had to do was find out how to change it and could look it up in a manual. Most of the logic was already there.

Because i was trying to improve existing code (which was pretty poorly written if i'm honest!) i was very aware of bad practises and i think this made my coding a lot better.

Ollie

[Zerce]

For newbies who don't know what concatenate variables is.... here's an explanation.

Instead of doing
echo "My name is $name, I'm $age years old";

You would do
echo "My name is " . $name . ", I'm " . $age . " years old";

That way the variable is not inside the quotes and you can make sure that php will parse it. This is better to do it to make sure you don't get any errors, especially when it is a downloadable script, where people may have different php versions installed or different server types that will treat it differently.

Kinda like XHTML... like <BR /> is not the same as <br /> etc...

[Danny.VBT]

Quote:

Originally Posted by Zerce For newbies who don't know what concatenate variables is.... here's an explanation. Instead of doing echo "My name is $name, I'm $age years old"; You would do echo "My name is " . $name . ", I'm " . $age . " years old"; That way the variable is not inside the quotes and you can make sure that php will parse it. This is better to do it to make sure you don't get any errors, especially when it is a downloadable script, where people may have different php versions installed or different server types that will treat it differently. Kinda like XHTML... like <BR /> is not the same as <br /> etc...

You would also want to use single quotes in the above case:

PHP Code:

echo 'My name is ' . $name . ', I'm ' . $age . ' years old; 


PHP will look for variables inside double quotes, with single quotes you will speed up processing time.

[KeithMcL]

Quote:

Originally Posted by Danny.VBT You would also want to use single quotes in the above case: PHP Code: echo 'My name is ' . $name . ', I'm ' . $age . ' years old;  PHP will look for variables inside double quotes, with single quotes you will speed up processing time.

When using single quotes you need to be careful that you escape characters (with a backslash) that you want to be shown in the text (like the ' in I'm).

PHP Code:

echo 'My name is ' . $name . ', I\'m ' . $age . ' years old'; 


[harmor]

You don't need to concatenate variables. You only concatenate arrays

PHP Code:

echo "My name is ".$person['name'].", I'm ".$person['age']." years old"; 


[Brad]

Quote:

Originally Posted by harmor You don't need to concatenate variables. You only concatenate arrays PHP Code: echo "My name is ".$person['name'].", I'm ".$person['age']." years old";

I like to end quoting as soon as there is no more text to be passed, I do a lot of things like this in my code these days even when using double quotes;

PHP Code:

print('Hi my name is' . $name); 


Also you can use an array inside of the double quotes if you do this instead;

PHP Code:

print("My name is {$person['name']}, I'm {$person['age']} years old"); 


[nitr021]

Quote:

Originally Posted by harmor You don't need to concatenate variables. You only concatenate arrays PHP Code: echo "My name is ".$person['name'].", I'm ".$person['age']." years old";

ok seriously that sounds stupid.
using "" in php slows your script down by milliseconds and uses a few more bytes to process as php needs to find the variables within "".
It is fine to use "" if you have some low traffic webpage where only 1-10 people visits it. But if you are aiming your script to be used on high end of the market where 1000's of page view will be generated then you would need to use single quotes to save money and time.

your way is just bad practice.

[Brad]

Quote:

Originally Posted by nitr021 ok seriously that sounds stupid. using "" in php slows your script down by milliseconds and uses a few more bytes to process as php needs to find the variables within "". It is fine to use "" if you have some low traffic webpage where only 1-10 people visits it. But if you are aiming your script to be used on high end of the market where 1000's of page view will be generated then you would need to use single quotes to save money and time. your way is just bad practice.

http://us3.php.net/manual/en/function.print.php#66392

[nitr021]

ty for that.

[nichky]

uhm, if you would pardon my newbie-ish question... by "220 posts" for the premium small plan provided by Xen Hosting, does it mean that my forum is restricted to only 220 posts?

edit: don't mind me, i found out what it means already,