CODEWITHSUNDEEP
pythonlistsumitertools-groupby
Zen4ttitude
Zen4ttitude

Reputation: 161

Sum categories by unique values in list in python

I have this list:

[('2023-03-15', 'paris', 'flight', 4),
('2023-03-21', 'berlin', 'flight', 2),
('2023-03-01', 'madrid', 'drive', 10),
('2023-03-04', 'madrid', 'cycling', 3),
('2023-03-08', 'rome', 'train', 9),
('2023-03-11', 'amsterdam', 'flight', 5),
('2023-03-14', 'london', 'boat', 1)]

How do you reproduce the same list syntax summing similar activities like "flight", taking the latest date as the date for the totals for each activity in the new list? Summing the integers associated.

Upvotes: 0

Views: 43

Answers (3)

Andrew Holmgren
Andrew Holmgren

Reputation: 1275

You didn't really specify what you were looking for in the output, but I took it as you are trying to condense all the entries of a given key into the entry with the latest date and the sum of the integers.

import itertools

input_list = [('2023-03-15', 'paris', 'flight', 4),
('2023-03-21', 'berlin', 'flight', 2),
('2023-03-01', 'madrid', 'drive', 10),
('2023-03-04', 'madrid', 'cycling', 3),
('2023-03-08', 'rome', 'train', 9),
('2023-03-11', 'amsterdam', 'flight', 5),
('2023-03-14', 'london', 'boat', 1)

key = 'flight'
sorted_list = sorted(input_list, key=lambda x: x[2])
groups = itertools.groupby(sorted_list, key=lambda x: x[2])
for k, g in groups:
    if k == key:
        group_list = list(g)
        sum_value = sum(x[3] for x in group_list)
        selected_value = list(max(group_list, key=lambda x: x[0]))
        selected_value[-1] = sum_value
print(selected_value)

Output

['2023-03-21', 'berlin', 'flight', 11]

Upvotes: 0

Yash Mehta
Yash Mehta

Reputation: 2006

Code:

lis=[('2023-03-15', 'paris', 'flight', 4),
     ('2023-03-21', 'berlin', 'flight', 2),
     ('2023-03-01', 'madrid', 'drive', 10),
     ('2023-03-04', 'madrid', 'cycling', 3),
     ('2023-03-08', 'rome', 'train', 9),
     ('2023-03-11', 'amsterdam', 'flight', 5),
     ('2023-03-14', 'london', 'boat', 1)]

totals={}
for dt,loc,activ,num in lis:
    if activ in totals:
        totals[activ]['total']+=num
        totals[activ]['latest_date']=max(totals[activ]['latest_date'],dt)
    else:
        totals[activ]={'total': num, 'latest_date': dt}

res=[(totals[activ]['latest_date'], loc, activ, totals[activ]['total']) for dt,loc,activ,num in lis if activ in totals]

print(res)

Output:

[('2023-03-21', 'paris', 'flight', 11), 
 ('2023-03-21', 'berlin', 'flight', 11), 
 ('2023-03-01', 'madrid', 'drive', 10), 
 ('2023-03-04', 'madrid', 'cycling', 3), 
 ('2023-03-08', 'rome', 'train', 9), 
 ('2023-03-21', 'amsterdam', 'flight', 11), 
 ('2023-03-14', 'london', 'boat', 1)]

Upvotes: 1

Elvin Jafarov
Elvin Jafarov

Reputation: 1467



original_list = [('2023-03-15', 'paris', 'flight', 4),
                 ('2023-03-21', 'berlin', 'flight', 2),
                 ('2023-03-01', 'madrid', 'drive', 10),
                 ('2023-03-04', 'madrid', 'cycling', 3),
                 ('2023-03-08', 'rome', 'train', 9),
                 ('2023-03-11', 'amsterdam', 'flight', 5),
                 ('2023-03-14', 'london', 'boat', 1)]

activity_totals = {}
for date, city, activity, num in original_list:
    if activity not in activity_totals:
        activity_totals[activity] = (date, num)
    else:
        latest_date, total_num = activity_totals[activity]
        if date > latest_date:
            activity_totals[activity] = (date, total_num + num)
        else:
            activity_totals[activity] = (latest_date, total_num + num)

new_list = [(latest_date, city, activity, total_num) for activity, (latest_date, total_num) in activity_totals.items()]

print(new_list)

Upvotes: 0

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