What is the purpose of dynamically accessing $_SESSION in PHP?

When dynamically accessing $_SESSION in PHP, the purpose is to store and retrieve session data based on dynamic keys or values. This allows for flexibility in managing session variables and can be useful when working with dynamic data or user inputs.

// Dynamically access $_SESSION to store and retrieve session data based on dynamic keys
$key = "username";
$value = "john_doe";

// Store data in session
$_SESSION[$key] = $value;

// Retrieve data from session
echo $_SESSION[$key];