In PHP Laravel, you can retrieve route parameters in several ways and in different places. Below, I'll provide you with code examples for each method:

• Using the Route Facade: You can use the Route facade to access route parameters. Here's an example:

   $parameter = Route::current()->parameter('parameterName');

• Using the request Object: You can also retrieve route parameters using the request object's route() method:

   $parameter = request()->route('parameterName');

• Using Route Model Binding: If you have defined route model binding in your routes or controllers, Laravel will automatically retrieve the model instance associated with the parameter. For example:

   public function show(User $user) {
       // $user is an instance of the User model
   }

• Using the Route::input() Method: This method allows you to access route parameters directly:

   $parameter = Route::input('parameterName');

• Using Type-Hinting in Controller Methods: You can type-hint parameters in controller methods, and Laravel will automatically resolve them:

   public function show($parameterName) {
       // Laravel resolves $parameterName from the route parameter
   }

• Using the request() Helper Function: You can also use the request() helper function to retrieve route parameters:

   $parameter = request('parameterName');

• Using the $request Object direct parameter access: You can also use the $request->parameterName directly to retrieve route parameters:

   $parameter = $request->parameterName;

These are various ways to retrieve route parameters in Laravel, and you can choose the one that best fits your specific use case.