how to print session value in php code example

Example 1: destroy session php

<?php 
 session_start(); // start session
 session_destroy();  // Delete whole session
// OR
unset($_SESSION['username']); // delete any specific session only
?>

Example 2: set php varibianle session

<?php 
  // Start the session
  session_start();
?>
<!DOCTYPE html>
<html>
  <body>
  <?php
    // Set session variables
    $_SESSION["color"]= "blue";
    $_SESSION["animal"]= "dog";
    echo "The session variable are set up.";
  ?>
  </body>
</html>