how to set optional third parameter in routes of codeigniter

Certainly! To set an optional third parameter in routes using CodeIgniter, follow these steps:

1. Open the application/config/routes.php file in your CodeIgniter project.

2. Define your route with placeholders for the parameters you want. For example: php $route['products/(:any)/(:any)/(:any)'] = 'catalog/product_lookup/$1/$2/$3';

3. The placeholders (:any) represent segments in the URL. In this case, the third parameter is optional due to its placement and lack of constraints.

4. The route maps to the catalog controller's product_lookup method. The parameters captured in the URL segments are passed as arguments to this method.

5. If the URL contains three segments after /products/, all three will be passed as arguments. If there are only two segments, the third parameter will be considered optional and can be handled accordingly in your controller method:

php public function product_lookup($param1, $param2, $param3 = null) { // $param1, $param2 will always have values // $param3 will be null if not provided in the URL // Your code logic here }

1. The $param3 variable in the product_lookup method will be set to null if the third parameter is not present in the URL. You can check for its presence and handle it accordingly within your controller method.