Group dates into list based on value

I have a json object that I’m trying to group item together in.

sorted_stack = sorted(stack, key=itemgetter('Date'))
    for key, group in itertools.groupby(sorted_stack, key=lambda x:x['Date']):
        print(key)
        print(list(group))

this code returns values grouped by date as the key and then a list of teams and dates like this

 2020-03-08
[{'Team': 'ORL', 'Date': '2020-03-08'}, {'Team': 'ORL', 'Date': '2020-03-08'}, {'Team': 'ORL', 'Date': '2020-03-08'}, {'Team': 'PHO', 'Date': '2020-03-08'}, {'Team': 'PHO', 'Date': '2020-03-08'}, {'Team': 'PHO', 'Date': '2020-03-08'}, {'Team': 'PHO', 'Date': '2020-03-08'}, {'Team': 'MIN', 'Date': '2020-03-08'}, {'Team': 'MIN', 'Date': '2020-03-08'}, {'Team': 'MIN', 'Date': '2020-03-08'}]

However, I need it to return and key value pair like this

2020-03-08 : [{'Team': 'ORL', 'Date': ['2020-03-08', '2020-03-08', '2020-03-08']}, {'Team': 'PHO', 'Date': ['2020-03-08','2020-03-08', '2020-03-08', '2020-03-08']}, {'Team': 'MIN', 'Date': ['2020-03-08','2020-03-08', '2020-03-08']}

where all the dates for a specific team are in a list as the value for the key Date.

Answer

This is one approach using dict.setdefault

Ex:

for key, group in itertools.groupby(sorted_stack, key=lambda x:x['Date']):
    print(key)
    temp = {}
    for i in group:
        temp.setdefault(i['Team'], []).append(i['Date'])
    print(temp)
    #OR
    print([{"Team": k, "Date": v} for k, v in temp.items()])