convert value from routes/uri to string

It's easier with Query Builder syntax:

PHP Code:

public function user($key, $value)
{
   return $this->db->where($key,$value)->get('users')->row();
} 


Previously thanks for the answer, I know and before I tried using the query builder and it worked.
but the query builder has restrictions (in my opinion). therefore I used a manual query because of its flexibility and I decided to always use manual queries.

But I will try to understand the query builder to be more flexible.