Here is a very simple answer my friend:
df['nb_months'] = ((df.date2 - df.date1)/np.timedelta64(1, 'M'))
and now:
df['nb_months'] = df['nb_months'].astype(int)
df.assign( Months= (df.Date2.dt.year - df.Date1.dt.year) * 12 + (df.Date2.dt.month - df.Date1.dt.month)) Date1 Date2 Months0 2016-04-07 2017-02-01 101 2017-02-01 2017-03-05 1
An alternative, possibly more elegant solution isdf.Date2.dt.to_period('M') - df.Date1.dt.to_period('M'), which avoids rounding errors.
df.Date2.dt.to_period('M') - df.Date1.dt.to_period('M')