These days  I found a great PHP tutorial series called “Diving into PHP”. It is made by Jeffrey Way from Theme Forest and it has 15 episodes till now. It starts from scrach and slowly builds up to advanced topics that is why it is great for PHP beginers and for advanced users.

Some resource links :

WAMP

MAMP

XAMPP

Enough with the chitchat, lets dive you in:

Downloading the Language

1st episode will teach you to install the support applications that will build the developing environment (Get the source files):

Variables

2nd episode shows you how to work with variables and using single/double quotes (Get the source files):

Passing Values From Page to Page

3rd eppisode will get you in how to pass variables from page to page using GET and POST (Get the source files):

Multiple Variables and the “foreach” Statement

4th episode continues on how to pass multiple variables from page to page you will have a review for “foreach” statement (Get the source files):

Refactoring, Arrays, and Functions – Oh My!

5th episode reviews arrays, refactoring, functions, and includes (Get the source files):

Includes

6th episode gets you into somehow more advanced topics like “include” statement (Get the source files):

Regular Expressions

7th episode will teach you how to use regular expressions with PHP. Over the course of about ten minutes, you’ll be learning about “preg_match()” and “preg_replace()” functions to validate a form. (Get the source files):

Strings

8th episode will explain to you how to use the strings. Single quotes, double quotes and a not so known concept called heredocs (Get the source files):

Detecting First-Time Visitors

Starting with 9th episode, you’ll going to learn some practical uses of PHP. In this episode, you’ll be shown how to detect whether or not a user has visited your site previously (Get the source files):

Getting Started With MySql

In 10th episodes you’ll be shown how easy it is to get up and running with MySql. We’ll also review the correct way to retrieve information from your new database (Get the source files):

SQL Insert Statements

Continuing on from Day 10, you’ll review SQL insert statements that will allow you to add new rows to your MySql database with PHP. Additionally, you’ll learn one of the ways to loop through an array and thats the foreach statement. (Get the source files)

Thats it for the moment. Stay tuned for the upcoming screen cast. Don’t forget that screen casts are originated from http://blog.themeforest.net/tutorials/diving-into-php-video-series/.

This is a very interesting tutorial if you would like to build your own calculator written in PHP. It guides you through all the steps and it is very clean written and has a good error checking. It uses if, witch and other math functions.

And … from users recommendation I have inserted the php code used in the video:

<?php

if ( !$_POST['submit'] ) {
	echo "<table border=\"0\" cellspacing=\"3\" cellpadding=\"3\">\n";
	echo "<form method=\"post\" action=\"calc.php\">\n";
	echo "<tr><td><input type=\"text\" name=\"num1\"/></td>\n";
	echo "<td><select name=\"sign\"><option value=\"plus\">+</option>\n<option value=\"minus\">-</option>\n<option value=\"multi\">*</option>\n<option value=\"divide\">/</option></select></td>\n";
	echo "<td><input type=\"text\" name=\"num2\"/></td>\n";
	echo "<td><input type=\"submit\" name=\"submit\" value=\"Calculate\"/></td></tr>\n";
	echo "</form></table>\n"; 
} else {
	$num1 = $_POST['num1'];
	$num2 = $_POST['num2'];
	$sign = $_POST['sign'];

	$errors = array();

	$signs = array('plus', 'minus', 'multi', 'divide');

	if (!$num1) {
		$errors[] = "You did not supplied the first number";
	} else {
		if (!$num2) {
			$errors[] = "You did not supplied the second number";
		} else {
			if(!$sign) {
				$errors[] = "You did not supplied a sign to calculate your two numbers";				
			} else {
				if (!in_array($sign, $signs)) {
					$errors[] = "Invalid sign for calculation";
				} else {
					if($sign == "divide") {
						if ($num2 == 0) {
							$errors[] = "You cannot divide by 0. Please choose a different number to divide with";
						}
					}

					if (!is_numeric($num1)) {
						$errors[] = "Your first number is not numeric";
					} else {
						if (!is_numeric($num2)) {
							$errors[] = "Your second number is not numeric";
						}
					}					
				}
			}
		}
	}
	if (count($errors)>0) {
		echo "The fallowing errors occurred:<br>\n";
		foreach ($errors as $error) {
			echo $error."<br>\n";
		}
	} else {
		switch ($sign) {
			case 'plus':
				$equation = $num1 + $num2;
				$written = $num1 . " + " . $num2;
			break;

			case 'minus':
				$equation = $num1 - $num2;
				$written = $num1 . " - " . $num2;
			break;

			case 'multi':
				$equation = $num1 * $num2;
				$written = $num1 . " * " . $num2;
			break;

			case 'divide':
				$equation = $num1 / $num2;
				$written = $num1 . " / " . $num2;
			break;

			default :
				$equation = "";
				$written = "";
			break;
		}

		echo $written . " = " . $equation; 
	}
}
?>