Here is a one-liner standard library version: from itertools import groupby keyfunc = lambda x: x['thing'] [{'thing': name, 'count': sum(t['count'] for

Here is a one-liner standard library version: from itertools import groupby keyfunc = lambda x: x['thing'] [{'thing': name, 'count': sum(t['count'] for t in things)} for name,things in groupby(sorted(mylist, key=keyfunc), keyfunc)]