how to send a value in the parameter without using the parameter name in the url?

[eluser]vindhyareddy[/eluser]
I am following the following tutorial.
http://net.tutsplus.com/tutorials/php/wo...igniter-2/

../index.php/example_api/users is the way how a url is being called.

Consider a url :

../index.php/example_api/user_type/fulltime/userid/12

This give the user details of the user bearing id 12 and a fulltime student.

Second e.g. :
../index.php/example_api/fulltime/userid/12

How do I create this url? Like as in this url user_type(parameter name) has not been used.Directly a value has been used.