PHP

What is php?

PHP (Hypertext Preprocessor) is a widely-used open-source scripting language that is especially suited for web development and can be embedded into HTML. Here’s a breakdown:

  • Server-Side Scripting: PHP code is executed on the server, and the results are sent to the user’s web browser as HTML. This contrasts with client-side scripting languages like JavaScript, which are executed in the browser.
  • Dynamic Web Pages: PHP allows you to create dynamic web pages that can change content based on user input, database information, or other factors.
  • Database Interaction: PHP can connect to various databases (like MySQL, PostgreSQL, and Oracle) to store and retrieve data. This is essential for building web applications that require data management.
  • Open Source: PHP is open-source, meaning it’s free to use and distribute. This has contributed to its widespread adoption.
  • Cross-Platform: PHP runs on various operating systems, including Windows, Linux, and macOS.
  • Uses:
    • Building websites and web applications
    • Developing e-commerce platforms
    • Creating content management systems (CMS) like WordPress, Drupal, and Joomla
    • Handling form data
    • Generating dynamic page content.

Basics

IO

  • Print statement
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    <?php
    echo "Hello, World!"; // Outputs text to the screen
?>

Comments and variables

  • Comments

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    // This is a comment

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    /*
This is a 
multi-line comment
*/

  • Variables

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    <?php
    $name = "John";
    $age = 25;
    echo $name; // Outputs: John
?>

Control statement

  • If-else statements

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    <?php
    $age = 18;

    if ($age >= 18) {
        echo "You are an adult.";
    } else {
        echo "You are a minor.";
    }
?>

  • Switch statements

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    <?php
    $day = 2;

    switch ($day) {
        case 1:
            echo "Monday";
            break;
        case 2:
            echo "Tuesday";
            break;
        default:
            echo "Other day";
    }
?>