This is probably a stupid question but got some writers block or something.

Got two collections:
colPrices has share prices and the key of the collection is a share code.
colShares has a number of shares held and the key of the collection is also the share code.

The two collections might not be in the same order (although they probable will be) but they will have the same number of elements. So each share code will be in each collection.

Want to iterate through the Prices collection and find any entries with a 0 price then look in the Shares collection if there is a value > 0 there for the same share. How do I get the value of the key from one collection so I can use it to look in the other collection for the same key (code)?