Doesn't detract from any of your points, just as a FYI: Python has a counter data structure in the standard library. The "pythonic" way would be something like

Doesn't detract from any of your points, just as a FYI: Python has a counter data structure in the standard library. The "pythonic" way would be something like this: groupby_dict = Counter() for r in response: groupby_dict.update({r['thing']: r['count']}) Counter is a subclass of dict, no further conversion needed.