import pandas as pd
from pandas.tseries.offsets import MonthEnd
## 像2022-01这样格式的时间字符串
df1 = pd.DataFrame({'date': ['2022-01', '2022-02', '2022-03', '2022-04', '2022-05']})
df1['new_date'] = df1['date'].astype('datetime64')+ MonthEnd()
## 像202201这样格式的时间字符串
df2 = pd.DataFrame({'date': ['202201', '202202', '202203', '202204', '202205']})
df2['new_date'] = pd.to_datetime(df2['date'], format='%Y%m') + MonthEnd()
print(df1,'n',df2)
date new_date
0 2022-01 2022-01-31
1 2022-02 2022-02-28
2 2022-03 2022-03-31
3 2022-04 2022-04-30
4 2022-05 2022-05-31
date new_date
0 202201 2022-01-31
1 202202 2022-02-28
2 202203 2022-03-31
3 202204 2022-04-30
4 202205 2022-05-31
