Consider some strings Par1, Par2, Par3. Could you please tell me how to compose filename/string in the form

    filename="experiment-Par1_number-Par2_position-Par3.dat"

E.g., with the following example,
Par1="Exp";
Par2="11";
Par3="End";

the filename would be

    filename="experiment-Exp_number-11_position-End.dat"