Find number of months between two dates in python

Shanoo :

I have a date object and a date column 'date1' in pandas dataframe 'df' as below:

date = '202107'

df
    date1 
0   2021-07-01   
1   2021-08-01   
2   2021-09-01   
3   2021-10-01   
4   2021-11-01

I want to create a column 'months' in df where

months = (date1 + 1month) - date

My output dataframe should look like below:

df
    date1        months
0   2021-07-01   1
1   2021-08-01   2
2   2021-09-01   3
3   2021-10-01   4
4   2021-11-01   5

YOBEN_S :

IIUC

s=(df.date1-pd.to_datetime(date,format='%Y%m'))//np.timedelta64(1, 'M')+1
Out[118]: 
0    1
1    2
2    3
3    4
4    5
Name: date1, dtype: int64
df['months']=s