I'm assuming that you are using the datafeeds.list method of the Shopping API
The
datafeeds.list method returns an array of objects, each object is for a separate feed ID.
You'd need to loop through the array, get the inner object, then get the ID property and test it against your
required feed ID to get the feed that you want.
Your other option is to use the datafeeds.custombatch method,
which has a stated intent of:
Quote:
Deletes, fetches, gets, inserts and updates multiple datafeeds in a single request.
End Quote:
However, I'm wondering if you only enter one feed ID in the Batch resource that it could work as a query
to just return one feed.
I don't know if it's worth going through the trouble to figure out how to configure that request,
rather than just getting all feeds, and looping through them.