How can I create a nested dictionary inside a nested dictionary via for loop?-CodePudding

how can i create something like this

in the kitchen  :  {'2010-01-05': {'activity': '...', 'activity':'...', 'activity':'...'}, '2010-01-06':{'activity':'...', 'activity':'...'}}

if my list looks like this?

my_list= [
    ['2010-01-05 12:32:05', 'in the kitchen', 'ON'],
    ['2010-01-05 12:32:08', 'in the kitchen', 'ON'],
    ['2010-01-05 12:32:10', 'in the kitchen', 'ON'],
    ['2010-01-06 02:32:11', 'in the kitchen', 'ON'],
    ['2010-01-06 02:32:20', 'in the kitchen', 'ON']]

i already have all the information i want to insert after 'activity', i just need a snippet on how could i achive this kind of output. i tried doing this

my_Dict= {}
for i, item in enumerate(my_list): 
..... # calculating for every item the info i want to put in my dict .....
 res = str(time)
 p = item[0].split()  # because i only want the date as key, not also the time
 if item[1] not in my_Dict.keys():
        my_Dict[item[1]] = dict()
           if item[0] not in my_Dict.keys():
               my_Dict[item[1]][p[0]] = dict()

               my_Dict[item[1]][p[0]]["activity"] = res

but the output it gives is

in the kitchen  :  {'2010-01-05': {'activity': '...'}}

not considering the other times the sensor was active and not considering even the next day of activity, it just consider the first element

CodePudding user response：

You're trying to use dictionary when what you probably need is a List.

You'll have to use List of dictionary, which means your data should look like :

in the kitchen  :  {'2010-01-05': [{'activity': '...'}, {'activity':'...'}, {'activity':'...'}], '2010-01-06':[{'activity':'...'}, {'activity':'...'}] }

so your code would probably look similar to

my_dict["2010-01-05"].append({"activity" : res})

where my_dict["2010-01-05"] should be initialized as list as needed.

CodePudding user response：

I'd use a defaultdict for that. It allows you to directly modify dictionary values without the need to perform if x in dict checks.

from collections import defaultdict

# nested dict: {'location': {'date': ['action']}}
result = defaultdict(lambda: defaultdict(list))

for date, location, activity in my_list:
    result[location][date.split()[0]].append(activity)

The result looks like this and works like a regular nested dict.

defaultdict(<function __main__.<lambda>()>,
            {'in the kitchen': defaultdict(list,
                         {'2010-01-05': ['ON', 'ON', 'ON'],
                          '2010-01-06': ['ON', 'ON']})})