我想在以下df:中添加4列日期
entry_date sum entry_date payment_date
2000-01-05 8543304 2000-01-05 2000-02-18
2000-01-06 370224 2000-01-06 2000-03-24
2000-01-07 12040645 2000-01-07 2000-03-15
2000-01-10 14633220 2000-01-10 2000-03-22
2000-01-10 480648 2000-01-10 2000-03-21
... ... ... ... ... ... ... ... ... ...
2020-12-29 1779688 2020-12-29 2021-01-25
2020-12-30 596003 2020-12-30 2021-03-12
2020-12-30 1412306 2020-12-30 2021-02-04
2020-12-30 7588376 2020-12-30 2021-03-18
2020-12-31 11229071 2020-12-31 2021-02-01
5478 rows × 9 columns
我想创建4列日期：如果entry_date.day<13.
我已经编写了以下函数：
def get_15th_day_of_month(dt):
if dt.day < 13:
return dt.replace(day=15)
new_month = (dt.month + 1)
new_year = dt.year
while new_month > 12:
new_month = new_month - 12
new_year = new_year + 1
new_day = 15
return datetime(dt.year, new_month, new_day, calendar.monthrange(dt.year, new_month))
但由于缺乏经验，我不知道如何有效地实施。我写了一个只返回零的循环。如果15日不是工作日，也可以在下一个工作日进行抵消。
最终的数据帧(在我的梦中(应该如下所示：
entry_date sum entry_date expiry_date date1 date2 date3 date4
2000-01-05 8543304 2000-01-05 2000-02-18 2000-02-15 2000-03-15 2000-04-15 2000-05-15
2000-01-06 370224 2000-01-06 2000-03-24 2000-01-15 2000-02-15 2000-03-15 2000-03-15
2000-01-07 12040645 2000-01-13 2000-03-15 2000-02-15 2000-03-15 2000-04-15 2000-05-15
2000-01-10 14633220 2000-01-10 2000-03-22
2000-01-10 480648 2000-01-10 2000-03-21
... ... ... ... ... ... ... ... ... ...... ... ... ... ... ... ... ... ... ... ... ... ... ...
2020-12-29 1779688 2020-12-29 2021-01-25
2020-12-30 596003 2020-12-30 2021-03-12
2020-12-30 1412306 2020-12-30 2021-02-04
2020-12-30 7588376 2020-12-30 2021-03-18
2020-12-31 11229071 2020-12-31 2021-02-01
5478 rows × 9 columns
您可以使用日期时间的月份周期，如果条件不匹配，则添加一个月，然后添加14 Days(因为每个月的第一天已经存在(：
df['entry_date'] = pd.to_datetime(df['entry_date'])
m = df['entry_date'].dt.day < 13
per = df['entry_date'].dt.to_period('m')
for i in range(4):
df[f'date{i + 1}'] = per.where(m, per + 1).add(i).dt.to_timestamp()+pd.Timedelta('14D')
print (df)
sum entry_date payment_date date1 date2 date3
2000-01-05 8543304 2000-01-05 2000-02-18 2000-01-15 2000-02-15 2000-03-15
2000-01-06 370224 2000-01-06 2000-03-24 2000-01-15 2000-02-15 2000-03-15
2000-01-07 12040645 2000-01-13 2000-03-15 2000-02-15 2000-03-15 2000-04-15
2000-01-10 14633220 2000-01-10 2000-03-22 2000-01-15 2000-02-15 2000-03-15
2000-01-10 480648 2000-01-10 2000-03-21 2000-01-15 2000-02-15 2000-03-15
2020-12-29 1779688 2020-12-29 2021-01-25 2021-01-15 2021-02-15 2021-03-15
2020-12-30 596003 2020-12-30 2021-03-12 2021-01-15 2021-02-15 2021-03-15
2020-12-30 1412306 2020-12-30 2021-02-04 2021-01-15 2021-02-15 2021-03-15
2020-12-30 7588376 2020-12-30 2021-03-18 2021-01-15 2021-02-15 2021-03-15
2020-12-31 11229071 2020-12-31 2021-02-01 2021-01-15 2021-02-15 2021-03-15
date4
2000-01-05 2000-04-15
2000-01-06 2000-04-15
2000-01-07 2000-05-15
2000-01-10 2000-04-15
2000-01-10 2000-04-15
2020-12-29 2021-04-15
2020-12-30 2021-04-15
2020-12-30 2021-04-15
2020-12-30 2021-04-15
2020-12-31 2021-04-15