💻

Essential PHP Programming Concepts

Aug 8, 2024

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.

Full transcript