php basics code example

Example 1: how to use php

// Firstly you must have PHP installed & running a web server
// This could be Apache, Nginx, etc...
// Or for quick testing purposes and for the purpose
// of this example, you could run
// PHP's own dev server from a shell
php -S 127.0.0.1:8080 -t your-web-directory-location
// This will start a web server on localhost port 8080
// The -t switch sets the document root, this is where your
// home page, typically index.php will be situated

// very basic index.php example
<?php
	echo "Hello, world!";   
?>
  
// You can now go to a browser and enter 127.0.0.1:8080
// You will presented with your simple web page
// Hello, world!

Example 2: php

<?php
class BaseClass {
   public function test() {
       echo "BaseClass::test() called\n";
   }
   
   final public function moreTesting() {
       echo "BaseClass::moreTesting() called\n";
   }
}

class ChildClass extends BaseClass {
   public function moreTesting() {
       echo "ChildClass::moreTesting() called\n";
   }
}
// Results in Fatal error: Cannot override final method BaseClass::moreTesting()
?>

Example 3: php

<?php
class Connection
{
    protected $link;
    private $dsn, $username, $password;
    
    public function __construct($dsn, $username, $password)
    {
        $this->dsn = $dsn;
        $this->username = $username;
        $this->password = $password;
        $this->connect();
    }
    
    private function connect()
    {
        $this->link = new PDO($this->dsn, $this->username, $this->password);
    }
    
    public function __sleep()
    {
        return array('dsn', 'username', 'password');
    }
    
    public function __wakeup()
    {
        $this->connect();
    }
}?>

Example 4: ?? php

?: // !empty()
?? // isset()

Example 5: php

PHP is a general-purpose scripting language especially suited to
web development. 
It was originally created by Danish-Canadian programmer 
Rasmus Lerdorf in 1994; 
the PHP reference implementation is now produced by The PHP Group

Implementation language: C (primarily; some components C++)

Example 6: basic php

<?php
  
  // This is a comment
  
  echo 'Hello, World!';
  
  // And this outputs Hello, World!
  
?>