List Of Integers Indexed By Key Or Index?

I would like to create a list of integers. The list will be items that I need to index by a key (string) or an index, which I set. For example I have items 1, 2, and 5. I would like to call Array(5) = 1. Where the the 5 is indexing a particular item 5, not the 5th item in the array. Using Array("5") = 1 could work as well. I tried using a List, but the only index is the ordered element of the list. I tried a Collection, but I kept getting errors that the items of the Collection are read only. How can I do this?

To be more specific, I have a simple game application which has a Player class. Each Player is trying to collect hits of say 3 fields {1,2,5}. I need to store how many times a player hits each of the 3 fields. So, I would like to read and write using logic like player(1).field(5) = 5. I want to add an object to the Player class which stores the number of times each of the 3 fields has been hit.