python - Pandas:合并数据框中的重复字符串

Question

我有数据框。这是他们的一部分

       member_id          event_time                       event_path    event_duration  \
0        2333678 2016-12-27 04:17:16  youtube.com/watch?v=w5ZIb05NO58    12  
1        2333678 2016-12-27 04:17:26  youtube.com/watch?v=w5ZIb05NO58     12 
2        2333678 2016-12-27 04:17:36  youtube.com/watch?v=w5ZIb05NO58   10   
3        2333678 2016-12-27 04:17:40  youtube.com/watch?v=w5ZIb05NO58   35   
4        5611206 2016-12-30 17:16:01  youtube.com/watch?v=qZrQWA5IsKA   35   
5        5611206 2016-12-30 17:16:10  youtube.com/watch?v=qZrQWA5IsKA    12  
6        5611206 2016-12-30 17:16:27  youtube.com/watch?v=6YM5UhnElcE   10   
7        5611206 2016-12-30 17:16:37  youtube.com/watch?v=6YM5UhnElcE   10   
8        5611206 2016-12-30 17:16:47  youtube.com/watch?v=6YM5UhnElcE   10

期望输出

       member_id          event_time                       event_path   event_duration
0        2333678 2016-12-27 04:17:16  youtube.com/watch?v=w5ZIb05NO58    69     
4        5611206 2016-12-30 17:16:01  youtube.com/watch?v=qZrQWA5IsKA    47    
6        5611206 2016-12-30 17:16:27  youtube.com/watch?v=6YM5UhnElcE    30      

我用

g = (df.event_path != df.event_path.shift()).cumsum()
df = (df.groupby([df.member_id, df.event_time, g], sort=False).agg({'event_duration':'sum', 'event_path':'first'})
     .reset_index(level='event_path', drop=True)
     .reset_index()
     .reindex(columns=df.columns))

但它不会连接所有字符串。

Answer 1

如果您想获得 event_time 中每个组的第一项，您可以使用以下内容(您也已将其用于 event_path):

>>> df.groupby([df.member_id, df.event_path]).agg({'event_duration':'sum', 'event_time': 'first'}).reset_index().reindex(columns=df.columns)

    member_id event_time                       event_path  event_duration
0  2016-12-27   04:17:16  youtube.com/watch?v=w5ZIb05NO58              69
1  2016-12-30   17:16:27  youtube.com/watch?v=6YM5UhnElcE              30
2  2016-12-30   17:16:01  youtube.com/watch?v=qZrQWA5IsKA              47