PHP Course Lecture Notes

Introduction to PHP

• PHP is a powerful programming language for web development.
• It integrates well with HTML, enabling dynamic web pages.
• PHP is a server-side language that runs on the web server.

Course Overview

• Basics of PHP: Installation, creating PHP files, interaction with HTML.
• Advanced topics: Handling HTML form input, programming concepts (if statements, loops, arrays).
• Object-oriented programming: Classes and objects.

PHP Installation on Windows

1. Download PHP from php.net.
2. Choose the appropriate version (64-bit or 32-bit, thread-safe).
3. Extract the files to a designated folder (e.g., C:\PHP).
4. Configure the Windows PATH variable to include the PHP directory.
5. Verify installation through command prompt with php -v.

Text Editors for PHP

• Any text editor can be used for PHP (e.g., Notepad, Atom).
• Popular specialized editors include Atom (recommended in the tutorial).

Creating the First PHP File

• Start a local server with the command: php -S localhost:4000.
• Create a PHP file with the .php extension.
• PHP code is embedded within <?php ... ?> tags.

Example of Echo command

<?php
echo "Hello, world!";
?>

Getting User Input from Forms

• Use HTML forms to gather user input.
• Example of a form that collects a user’s name:

<form action="site.php" method="get">
  <input type="text" name="username"/>
  <input type="submit" value="Submit"/>
</form>

• Access user input in PHP with $_GET['username'].

Variables in PHP

• Variables store data values.
• Example:

$age = 25;
$name = "Mike";

Data Types in PHP

Types of Data

• Strings: e.g., "Hello"
• Integers: e.g., 25
• Floats: e.g., 25.5
• Booleans: e.g., true/false

Arrays

• An array is a container for multiple values.
• Example of creating an array:

$friends = array("Jim", "Pam", "Oscar");

• Accessing Array elements: $friends[0];
• Getting the count of array elements: count($friends);

Associative Arrays

• Store key-value pairs.
• Example:

$grades = array(
  "Jim" => "A+",
  "Pam" => "B-",
);

• Accessing elements: $grades['Jim'];

Functions in PHP

• Functions group code for reusability.
• Example of a simple function:

function sayHi($name) {
  return "Hello $name!";
}

If Statements

• Control program flow based on conditions.
• Example:

if ($isMale) {
  echo "You are male";
} else {
  echo "You are not male";
}

Switch Statements

• Simplifies comparing a value against multiple options.
• Example:

switch ($grade) {
  case "A":
    echo "You did amazing";
    break;
  default:
    echo "Invalid grade";
}

Loops in PHP

While Loops

• Execute a block of code while a condition is true.

For Loops

• Loop over a block of code a known number of times.

for ($i = 1; $i <= 5; $i++) {
  echo $i;
}

Including Files

• Use include to incorporate code from other files.
• Example:

include "header.php";

Classes and Objects

• Classes define new data types.
• Objects are instances of classes.

class Book {
  public $title;
  public $author;
}

Constructors

• Automatically execute when an object is created.
• Initialize object attributes.

function __construct($title, $author) {
  $this->title = $title;
  $this->author = $author;
}

Getters and Setters

• Control access to object properties using getter and setter functions.
• Example:

function getTitle() {
  return $this->title;
}
function setTitle($title) {
  $this->title = $title;
}

Inheritance

• Extend functionality of a Class to another Class.

class ItalianChef extends Chef {
  function makePasta() {
    echo "Making pasta";
  }
}

Conclusion

• PHP provides a powerful set of tools for web programming.
• Understanding its key features like functions, arrays, classes, and conditionals is essential for effective coding.