PHP Fundamentals: From Zero to Hero

Welcome to your comprehensive guide to PHP programming! Whether you're completely new to programming or coming from another language, this guide will take you from the basics to building real-world applications.

Table of Contents

• Getting Started with PHP
• PHP Basics
• Variables and Data Types
• Control Structures
• Functions
• Arrays and Array Functions
• Working with Forms
• Database Integration
• Object-Oriented Programming

Getting Started with PHP

PHP (Hypertext Preprocessor) is a server-side scripting language designed specifically for web development. Before diving into coding, you'll need:

• A web server (like Apache or Nginx)
• PHP installed (latest stable version recommended)
• A text editor or IDE (VS Code, PHPStorm, or Sublime Text)

Pro Tip: Start with XAMPP or WAMP for an all-in-one development environment that includes PHP, Apache, and MySQL.

PHP Basics

Every PHP script starts with <?php and ends with ?>. Here's your first PHP program:

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

Save this as index.php in your web server's directory and access it through your browser.

Variables and Data Types

PHP variables start with a $ symbol. PHP supports several data types:

<?php
    // String
    $name = "John Doe";
    
    // Integer
    $age = 25;
    
    // Float/Double
    $price = 19.99;
    
    // Boolean
    $isStudent = true;
    
    // Array
    $colors = ["red", "green", "blue"];
    
    // Null
    $nothing = null;
?>
        

Control Structures

PHP provides essential control structures for program flow:

<?php
    // If-else statement
    $age = 20;
    if ($age >= 18) {
        echo "You are an adult";
    } else {
        echo "You are a minor";
    }

    // Loops
    for ($i = 0; $i < 5; $i++) {
        echo "Iteration: $i\n";
    }

    // While loop
    $counter = 0;
    while ($counter < 3) {
        echo "Count: $counter\n";
        $counter++;
    }
?>
        

Functions

Functions help organize and reuse code:

<?php
    function calculateArea($length, $width) {
        return $length * $width;
    }

    // Function with default parameter
    function greet($name = "Guest") {
        return "Hello, $name!";
    }

    // Using the functions
    echo calculateArea(5, 3);  // Outputs: 15
    echo greet("John");        // Outputs: Hello, John!
    echo greet();              // Outputs: Hello, Guest!
?>
        

Arrays and Array Functions

PHP offers powerful array manipulation capabilities:

<?php
    // Indexed array
    $fruits = ["apple", "banana", "orange"];

    // Associative array
    $person = [
        "name" => "John Doe",
        "age" => 25,
        "city" => "New York"
    ];

    // Multidimensional array
    $students = [
        ["name" => "John", "grade" => 85],
        ["name" => "Jane", "grade" => 92]
    ];

    // Array functions
    sort($fruits);                 // Sort indexed array
    array_push($fruits, "mango"); // Add element
    $length = count($fruits);     // Get array length
?>
        

Working with Forms

Handle HTML forms and user input:

<?php
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
        $username = $_POST["username"];
        $email = $_POST["email"];
        
        // Validate input
        if (empty($username)) {
            echo "Username is required";
        } elseif (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
            echo "Invalid email format";
        } else {
            echo "Form submitted successfully";
        }
    }
?>

<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
    Username: <input type="text" name="username">
    Email: <input type="email" name="email">
    <input type="submit">
</form>
        

Database Integration

Connect and interact with MySQL databases:

<?php
    // Database connection
    $conn = new mysqli("localhost", "username", "password", "database");

    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }

    // Insert data
    $sql = "INSERT INTO users (name, email) VALUES (?, ?)";
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("ss", $name, $email);
    $stmt->execute();

    // Select data
    $result = $conn->query("SELECT * FROM users");
    while ($row = $result->fetch_assoc()) {
        echo $row["name"] . " - " . $row["email"] . "\n";
    }
?>
        

Object-Oriented Programming

PHP supports object-oriented programming:

<?php
    class User {
        private $name;
        private $email;

        public function __construct($name, $email) {
            $this->name = $name;
            $this->email = $email;
        }

        public function getName() {
            return $this->name;
        }

        public function getEmail() {
            return $this->email;
        }
    }

    // Create an object
    $user = new User("John Doe", "john@example.com");
    echo $user->getName();  // Outputs: John Doe
?>
        

Next Steps

After mastering these fundamentals, you can:

• Learn a PHP framework like Laravel or Symfony
• Explore advanced topics like security and optimization
• Build real-world web applications
• Practice with small projects to reinforce your learning