Help!!Create a dynamic calculated field.

Version 1

    Hello Everyone,


    Am fairly new to Tableau, can anyone help with this.

    I am trying to create a calculated field for 'Countries that start with any pick and ends with any pick" Using "location name".

    Basically, so the end user can type in any letter in the parameter, and they get the country in the view

    I have attached my worksheet. Please note, I already created a set that gives me the answer, but I want to use a calculated field to arrive at the same answer.