Custom Field & Shortcode

I created some custom fields and would like to how do the following:
1. District Field, field type – Selection, field values:
District 1, City
District 2, City Fringe
District 3, Outside City

If I use a shortcode to display the custom field, [distict], it will display the entire line as “District 3, Outside City”.

Is there anyway where I can display just District 3 or 3 instead of the entire line?

2. When I am using checkbox, feature, I may have 10 items in the field values. In the listings entry, I have checked only 5 items.
How do I use short code to display [feature] for checked only value?