compare to previous date in pandas-CodePudding

I need to build the new column about compare the previous date and the previous date must follow a special rule. I need to find the repeat purchase in past 3 months. I have no idea how can do this. There has some example and my expected output.

transaction.csv:

code,transaction_datetime
1,2021-12-01
1,2022-01-24
1,2022-05-29
2,2021-11-20
2,2022-04-12
2,2022-06-02
3,2021-04-23
3,2022-04-22

expected output:

code,transaction_datetime,repeat_purchase_P3M
1,2021-12-01,no
1,2022-01-24,2021-12-01
1,2022-05-29,no
2,2021-11-20,no
2,2022-04-12,no
2,2022-06-02,2022-04-12
3,2021-04-23,no
3,2022-04-22,no

Thanks in advance

CodePudding user response：

df = pd.read_csv('file.csv')
df.transaction_datetime = pd.to_datetime(df.transaction_datetime)
grouped = df.groupby('code')['transaction_datetime']
df['repeated_purchase_P3M'] = grouped.shift().dt.date.where(grouped.diff().dt.days < 90, 'no')

df

   code transaction_datetime repeated_purchase_P3M
0     1           2021-12-01                    no
1     1           2022-01-24            2021-12-01
2     1           2022-05-29                    no
3     2           2021-11-20                    no
4     2           2022-04-12                    no
5     2           2022-06-02            2022-04-12
6     3           2021-04-23                    no
7     3           2022-04-22                    no