How to summarize a column based on repeated values?

Question

I’m trying to sum the duration of the activities using a for loop with conditions.

mydf= {'Duration' : [14, 8, 6, 36, 12, 5, 3, 2, 4, 5, 8, 3, 14, 1, 27, 25, 117, 2, 962, 2, 2, 1], 
'Activity': ['Groom', 'Pause', 'Groom', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Sleep', 'Awaken', 'Groom', 'Pause', 'Groom', 'Eat', 'Cuddle', 'Come down', 'Dig', 'Forage']}
    df = pd.DataFrame(mydf)

I want to sum all the sleep duration together.

I tried:

Sleep_sum = [sum(df['Duration'] for i in df['Activity'] if [i+1]=='Sleep')]

but this gives me an error : TypeError: can only concatenate str (not "int") to str.

I also tried this:

for i in range of len(df):
     df['Activity'][i] == 'Sleep'
     if [i] = [i+1]
     df['Duration'].sum()

Essentially, I need to sum the duration of ‘Sleep" if it’s followed by another row == "Sleep".

Thank you for your time!

Asked By: I_will_learn

||

Source

Answer 1

You can create virtual groups to group consecutive activities (Sleep and other):

out = (df.groupby(df['Activity'].ne(df['Activity'].shift()).cumsum(), as_index=False)
         .agg({'Duration': 'sum', 'Activity': 'first'}))
print(out)

# Output
    Duration   Activity
0         14      Groom
1          8      Pause
2          6      Groom
3         92      Sleep
4          1     Awaken
5         27      Groom
6         25      Pause
7        117      Groom
8          2        Eat
9        962     Cuddle
10         2  Come down
11         2        Dig
12         1     Forage

Update

Just for Sleep activity:

m = df['Activity'] == 'Sleep'
sleep = (df.reset_index(drop=False)[m]
           .groupby(df['Activity'].ne(df['Activity'].shift()).cumsum())
           .agg({'index': 'first', 'Duration': 'sum', 'Activity': 'first'})
           .set_index('index'))

out = pd.concat([df[~m], sleep]).sort_index()
print(out)

# Output
    Duration   Activity
0         14      Groom
1          8      Pause
2          6      Groom
3         92      Sleep
13         1     Awaken
14        27      Groom
15        25      Pause
16       117      Groom
17         2        Eat
18       962     Cuddle
19         2  Come down
20         2        Dig
21         1     Forage

Answered By: Corralien

How to summarize a column based on repeated values?

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