PHP

PHP is a server side language, meaning you can't see the source code in your browser, because all of the stuff is done on the server. To start, get some web hosting (easy) or start your own server (not as easy), and create a .php file. Having a decent knowledge of HTML is highly recommended. If you've programmed in another web language such as ASP, or have knowledge of application languages like C++ or Java, learning PHP will be considerably easier.

Yeah… This is the ancient tradition of beginners starting out in any language. Here you go.

<?php
  echo "LOL HAI THER AMIDOINITRITE?";
  print("DICKS");
?>

Let's go over some rulez. (The word rules does not have a 'z' in it you miserable faggot).

All PHP code starts with <?php and ends with ?>. These are called delimiters. echo is a statement that basically prints out whatever is in the double quotes. It isn't a function. (printf() is though.) Since echo is a statement, much like require/include/exit/etc, using parenthesis around the value(s) to be echoed is optional. All statements in PHP that aren't if/else statements, while, for, do-while, for-each loops, functions, or classes end in semicolons.

We saw how echo can output text. But it can also output HTML code and JavaScript. Example here.

<?php
  echo "<b>bold text</b> <i>italic text</i>";
?>

This'll output bold text italic text, and if you look at the source of the PHP page, you'll see the HTML code in there.

Now we'll learn a little about variables. PHP is great because, unlike other languages, you don't need to specify what type of variable you are declaring (integer, Boolean, float, string, etc). PHP automatically identifies the type for you. Anyway, here we go.

<?php
$lolvar = 6;
$loldecimal = 3.12;
$lolstring = "This is a string.";
echo $lolvar;
echo $loldecimal;
echo $lolstring;
?>

Some things to note:

ALL VARIABLES START WITH THE DOLLAR SIGN ($) NO EXCEPTIONS When echoing a variable you don't need the double quotes You can also concatenate, or join together, two strings, like so:

<?php
$lol = "lol";
$wut = "wut";
$randomdigit = 2;
echo "Did you just use the meme " . $lol . " " .  $wut . " " .$randomdigit . " times?";
?>

This'll just echo out the line “Did you just use the meme lol wut 2 times?”.

Constants are like variables, except they do not begin with a dollar sign and cannot be changed or deleted once defined. It is usual practice to name constants in all capitals (much like macros in C/C++). You define constants with the define(); function:

<?php
define("MYCONSTANT", "Constant Value");
echo MYCONSTANT;
?>

This sends out “Constant Value”.

Always $_, ex: $_COOKIE, $_SERVER, $_GET, $_REQUEST, and $_POST Some can only be used before any output is sent

<?php
$ip = $_SERVER['REMOTE_ADDR'];
$ref = $_SERVER['HTTP_REFERER'];
echo $ip." Was referred by ".$ref."<br />";
$UserAgent = $_SERVER[HTTP_USER_AGENT];
$Software = $_SERVER['SERVER_SOFTWARE'];
echo "Their useragent was ".$UserAgent."<br />";
echo "Your server software is ".$Software;
?>

Will output something like:

0.0.0.0 Was referred by ----- Their useragent was Mozilla/5.0 Your server software is Apache/2.2.8 (----) DAV/2 mod_ssl/2.2.8 OpenSSL/0.9.8g mod_python/3.3.1 Python/2.5.1 mod_autoindex_color PHP/5.2.5 mod_perl/2.0.3 Perl/v5.8.8

(Depending on your server environment.)

The datatype a variable uses is usually implicit, meaning PHP will determine what type of variable it should use based on its contents. However, these are some of the datatypes at your disposal.

Boolean ex: $a = true; #has only 2 possible values, true or false
Integer ex: $b = 4; #holds whole numbers
String ex: $c = "Hello"; #holds a set of letters and numbers
Float ex: $d = 3.5252524; #holds numbers with decimals
Array ex: $e = array(5, 3, 1); #holds a list of any other type of data, be it an integer, string, boolean, etc.
Null ex: $f = NULL; #only holds null (nothing)

+ Addition
- Subtraction
* Multiplication
/ Division
% Division with remainder 

+= ex: n+=7, or N equals N+7
-=
*=
/=
%=
.=
=

&& , AND ex: if (($a>0) && ($a<10)){
|| , OR ex: if (($a==0)||($a==1)){
! , NOT ex: if ($a != 2) {

< Less than
> Greater than
== Equal to
!= Not equal
=== Identical
!== Not identical
<= Less than or equal to
>= Greater than or equal to

Now you have a basic understanding of printing things, now it's time to start something else. We will explore loops and conditional statements. Loops will pretty much do something a certain amount of times and conditional statements control what the program does if a condition is fulfilled or not.

Well, it's basically just if and switch, but the former is pretty useful. You have to know this one.

This essentially checks whether or not a condition is true.

<?php
$willdo = true;
if($willdo == true){
   echo "did";
}
?>

An else statement is an addition to an if statement which allows for another condition. If there's an else statement something happens regardless.

<?php
$wontdo = false;
if($wontdo == true){
   echo "did";
} else {
   echo "didn't";
}
?>

Else if statements allow for multiple conditions, if and only if the first condition before it was false.

<?php
$maydo = 99;
$maynotdo = false;
if($maynotdo == true){
   echo "did";
} elseif ($maydo == 99){
   echo "did anyway";
} else {
   echo "didn't";
}
?>

Also:

1. Conditions in parentheses just have to be true. You don't have to use an == or != if it's a boolean value (true/false)
2. There are logical operators like and (&&) and or (||)
3. a ! behind it means it's false, so if $dick is true, !$dick is false, and vice versa if $dick was false.

A substitute to a whole bunch of elseifs. It tests if a given value is equal to something. Cases can be any value. There's also a default.

<?php
switch ($value) {
case false:
   echo "value is 0";
   break;
case 17:
   echo "value is 1";
   break;
case "pigdog":
   echo "value is pigdog";
   break;
case NULL:
   echo "value is null";
   break;
default:
   echo "value is something else other than 0, 1, pigdog, or null.";
   break;
}
?>

There are three main loops: for loops, foreach loops, and while/do-while loops.

For this loop you simply declare a variable as a counter, and the loop will occur as many times as you want it until the counter reaches a certain number.

<?php
$counter = 0; 
for($counter = 0; $counter < 6; $counter++)
  {
  echo "HAI
";
 }
?>

What this code does is take the variable we made, and use it as a counter. As long as the variable, $counter, is less than 6, the ++ operator will add one to the value of $counter and then the code within the curly braces {} will be executed. So the output of this code is:

HAI

HAI

HAI

HAI

HAI

Some notes about this code:

1. The ++ operator adds one to a variable, and can be used on any variable. This is an example of a unary operator. You could also use – to subtract one from the variable. 2. Notice that the for loop did NOT end in a semicolon. This is intended. Loops and conditionals don't need a semicolon. But the code inside of the curly braces DOES need the semicolons.

This statement essentially sets the number of times something's done. In PHP you use it on arrays to run through every element in an array to do something or another.

<?php
$lolarray = array("lol", "rofl", "lmao");
foreach($lolarray as $value){
   echo $value . "</br">;
}
?>

This code will output:

lol

rofl

lmao

Also:

1. you might want to unset(), or destroy the variable you use. You never know. 2. foreach($array as $key ⇒ $value) will assign $key as a key, but it's basically the same.