Getting POST data or raw data

How to get POST data or raw data

 yourFunctionName(Request $req, $params){

      $req->input(); [This will display array]

      $req->input('key'); [This will display value of specific key]

      $params->parameterkey; [The parameter that you have set in routes files]

      $params->querystringkey; [The parameter that you have set in query string]
 }