Verticle to Horizontal

I have a verticle list (attached) of locations and dates. Some locations have more than one date. I want to be able to show each location and all dates that show up on the original list.

List:
Location 1 - 1/15
Location 2 - 1/18
Location 1 - 2/15

To look like this:
Location 1 1/15 2/15
Location 2 1/18

Thanks!