如果一行的条件为真,则标记整个组

resample 跳过了 WeekNum

df.assign(
    Public_Holiday_Week=
    df.resample('W-Wed', on='Date').Public_Holiday.transform('max')
)

         Date  WeekNum  Public_Holiday  Public_Holiday_Week
0  2015-01-01        1               1                    1
1  2015-01-02        1               0                    1
2  2015-01-03        1               0                    1
3  2015-01-04        1               0                    1
4  2015-01-05        1               0                    1
5  2015-01-06        1               0                    1
6  2015-01-07        1               0                    1
7  2015-01-08        2               0                    0
8  2015-01-09        2               0                    0
9  2015-01-10        2               0                    0
10 2015-01-11        2               0                    0
11 2015-01-12        2               0                    0
12 2015-01-13        2               0                    0

为了提高性能,不要使用 groupby WeekNum 1 isin ,上次将布尔值掩码强制转换为 int

weeks = df.loc[df['Public_Holiday'].eq(1), 'WeekNum']
df['Public_Holiday_Week'] = df['WeekNum'].isin(weeks).astype(int)

print (df)
         Date  WeekNum  Public_Holiday  Public_Holiday_Week
0    1/1/2015        1               1                    1
1    2/1/2015        1               0                    1
2    3/1/2015        1               0                    1
3    4/1/2015        1               0                    1
4    5/1/2015        1               0                    1
5    6/1/2015        1               0                    1
6    7/1/2015        1               0                    1
7    8/1/2015        2               0                    0
8    9/1/2015        2               0                    0
9   10/1/2015        2               0                    0
10  11/1/2015        2               0                    0
11  12/1/2015        2               0                    0
12  13/1/2015        2               0                    0

week

df['weeks'] = pd.to_datetime(df['Date'], dayfirst=True).dt.week

weeks = df.loc[df['Public_Holiday'].eq(1), 'weeks']
df['Public_Holiday_Week'] = df['weeks'].isin(weeks).astype(int)
print (df)
         Date  WeekNum  Public_Holiday  weeks  Public_Holiday_Week
0    1/1/2015        1               1      1                    1
1    2/1/2015        1               0      1                    1
2    3/1/2015        1               0      1                    1
3    4/1/2015        1               0      1                    1
4    5/1/2015        1               0      2                    0
5    6/1/2015        1               0      2                    0
6    7/1/2015        1               0      2                    0
7    8/1/2015        2               0      2                    0
8    9/1/2015        2               0      2                    0
9   10/1/2015        2               0      2                    0
10  11/1/2015        2               0      2                    0
11  12/1/2015        2               0      3                    0
12  13/1/2015        2               0      3                    0

groupby 和 max map

df['Public_Holiday_Week'] = df.WeekNum.map(df.groupby('WeekNum').Public_Holiday.max())
print(df)
         Date  WeekNum  Public_Holiday  Public_Holiday_Week
0    1/1/2015        1               1                    1
1    2/1/2015        1               0                    1
2    3/1/2015        1               0                    1
3    4/1/2015        1               0                    1
4    5/1/2015        1               0                    1
5    6/1/2015        1               0                    1
6    7/1/2015        1               0                    1
7    8/1/2015        2               0                    0
8    9/1/2015        2               0                    0
9   10/1/2015        2               0                    0
10  11/1/2015        2               0                    0
11  12/1/2015        2               0                    0
12  13/1/2015        2               0                    0

和 transform 最大值

df['Public_Holiday_Week'] = df.groupby('WeekNum').Public_Holiday.transform('max')

df['Public_Holiday_Week'] = (
     df.groupby(['WeekNum', df.Date.str.split('/', 1).str[1]])
      .Public_Holiday.transform('max')
)
print(df)
         Date  WeekNum  Public_Holiday  Public_Holiday_Week
0    1/1/2015        1               1                    1
1    2/1/2015        1               0                    1
2    3/1/2015        1               0                    1
3    4/1/2015        1               0                    1
4    5/1/2015        1               0                    1
5    6/1/2015        1               0                    1
6    7/1/2015        1               0                    1
7    8/1/2015        2               0                    0
8    9/1/2015        2               0                    0
9   10/1/2015        2               0                    0
10  11/1/2015        2               0                    0
11  12/1/2015        2               0                    0
12  13/1/2015        2               0                    0