update column values based on length temp dataframes based on source dataframe

Question

I have a data:

ID	closed	set	message_time
aaa	22:00	19:00	19:05
aaa	22:00	19:30	19:40
aaa	22:00	20:00	21:00
bbb	23:00	22:00	22:10
ccc	22:00	19:00	19:05
ccc	22:00	19:30	19:40

code is here:

import pandas as pd
df = pd.DataFrame({
    'ID': ['aaa', 'aaa', 'aaa', 'bbb', 'ccc', 'ccc'],
    'closed': ['22:00', '22:00', '22:00', '23:00', '22:00', '22:00'],
    'set': ['19:00', '19:30', '20:00', '22:00', '19:00', '19:30'],
    'message_time': ['19:05', '19:40', '21:00', '22:10', '19:05', '19:40']
})

I need to create new column named "newtime" based on several conditions:

We have temp_df for each of id, so length of temp_df where id = aaa is 3, for bbb is 1, for ccc is 2;
if length of temp_df == 1 then newtime = closed - set
if length of temp_df > 1 then
     for rows > 0 and < length
         newtime = set[row+1] - set[row]
     if row == length then newtime = closed[row] - set[row]

What is the best way ro realize that?

P. S. The needed output is:

ID	closed	set	message_time	newtime
aaa	22:00	19:00	19:05	30 min
aaa	22:00	19:30	19:40	30 min
aaa	22:00	20:00	21:00	120 min
bbb	23:00	22:00	22:10	60 min
ccc	22:00	19:00	19:05	30 min
ccc	22:00	19:30	19:40	150 min

Asked By: luibrain

||

Source

Answer 1

Convert to_timedelta and fillna the last row per group with the difference:

c = pd.to_timedelta(df['closed']+':00')
s = pd.to_timedelta(df['set']+':00')

df['newtime'] = s.groupby(df['ID']).diff(-1).mul(-1).fillna(c-s)

Output:

    ID closed    set message_time         newtime
0  aaa  22:00  19:00        19:05 0 days 00:30:00
1  aaa  22:00  19:30        19:40 0 days 00:30:00
2  aaa  22:00  20:00        21:00 0 days 02:00:00
3  bbb  23:00  22:00        22:10 0 days 01:00:00
4  ccc  22:00  19:00        19:05 0 days 00:30:00
5  ccc  22:00  19:30        19:40 0 days 02:30:00

If you need output as minutes:

df['newtime'] = (s.groupby(df['ID']).diff(-1).mul(-1)
                  .fillna(c-s)
                  .dt.total_seconds().div(60)
                )

Output:

    ID closed    set message_time  newtime
0  aaa  22:00  19:00        19:05     30.0
1  aaa  22:00  19:30        19:40     30.0
2  aaa  22:00  20:00        21:00    120.0
3  bbb  23:00  22:00        22:10     60.0
4  ccc  22:00  19:00        19:05     30.0
5  ccc  22:00  19:30        19:40    150.0

Answered By: mozway

update column values based on length temp dataframes based on source dataframe

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