pandas series repeat n time and change column value

Question

I have input data like this.

NAME | PLACE | DATE
  A  |   X   | 2020-04-30
  B  |   Y   | 2019-04-30

i want to duplicate 5 times and change d

Answer 1

Use:

df['Date'] = pd.to_datetime(df['Date'])

y = np.array([pd.offsets.DateOffset(years=_) for _ in np.tile(range(6), len(df.index))])
df = df.reindex(df.index.repeat(6)).assign(Date=lambda x: x['Date'] + y)

Details:

Create a np.array of DateOffset objects that needs to be added to the Date column to get the desired year offset.

print(y)
array([, ,
       , ,
       , ,
       , ,
       , ,
       , ], dtype=object)

Use reindex to reindex the dataframe as required and use assign to add the Date with the years.

print(df)
  Name Place       Date
0    A     X 2020-04-30
0    A     X 2021-04-30
0    A     X 2022-04-30
0    A     X 2023-04-30
0    A     X 2024-04-30
0    A     X 2025-04-30
1    B     Y 2019-04-30
1    B     Y 2020-04-30
1    B     Y 2021-04-30
1    B     Y 2022-04-30
1    B     Y 2023-04-30
1    B     Y 2024-04-30