python - 查找多列条目之间的日期差异

Question

df1=

Date     Team1     Team2
6/1      Boston    New York
6/13     New York  Boston
6/27     Boston    New York

我正在尝试计算自上次波士顿出现在任一列中以来的天数，但我只能弄清楚如何使用 df1['自波士顿比赛以来的天数'] = df1. groupby('Team1')['日期'].diff().fillna(0)

我想要的输出是:

Date     Team1     Team2      Days since Boston played
6/1      Boston    New York   0
6/13     New York  Boston     12
6/27     Boston    New York   14

编辑 - 扩展数据框以了解如何将其应用于所有团队，而不仅仅是一个团队我想要的输出是:

Date     Team1     Team2      Days since **Team1** played
6/1      Boston    New York   0
6/13     New York  Chicago    12
6/27     Boston    New York   14
6/28     Chicago   Boston     15

Answer 1

使用 isin 检查 Boston 是否存在于 team1 或 team2 中并查找 timedelta

df['Date'] = pd.to_datetime(df['Date'], format = '%m/%d')

df.loc[df.isin(['Boston']).any(1),'Days since Boston played'] = df.loc[df.isin(['Boston']).any(1), 'Date'].diff().dt.days


    Date        Team1       Team2       Days since Boston played
0   1900-06-01  Boston      New York    NaN
1   1900-06-13  New York    Boston      12.0
2   1900-06-27  Boston      New York    14.0

如果您希望日期列恢复原始格式，可以使用 strftime

df['Date'] = df['Date'].dt.strftime('%m/%d')

    Date    Team1       Team2       Days since Boston played
0   06/01   Boston      New York    NaN
1   06/13   New York    Boston      12.0
2   06/27   Boston      New York    14.0