从数据帧中减去两行

Question

我有一个包含两列的数据框：事件和日期。

    created_at           event
0   2020-11-16 13:41:34  meeting-created
1   2020-11-16 13:49:52  meeting-ended
2   2020-11-16 14:01:36  meeting-created
3   2020-11-16 15:16:24  meeting-ended

我想计算会议的总持续时间，因此我需要先减去两个日期，然后再减去最后两个日期。知道数据框中可能有更多行。

Answer 1

如果总是有对减去过滤值并将第二个 Series 转换为 numpy 数组，我相信您需要：

df['created_at'] = pd.to_datetime(df['created_at'])

s1 = df.loc[df['event'].eq('meeting-ended'), 'created_at']
s2 = df.loc[df['event'].eq('meeting-created'), 'created_at']

df['new'] = s1.sub(s2.to_numpy())
print (df)
           created_at            event             new
0 2020-11-16 13:41:34  meeting-created             NaT
1 2020-11-16 13:49:52    meeting-ended 0 days 00:08:18
2 2020-11-16 14:01:36  meeting-created             NaT
3 2020-11-16 15:16:24    meeting-ended 0 days 01:14:48