Pandas create dataframe from one row

Question

Let us say i have some dataframe df and I want to create a new dataframe new_df with n rows each being the same as row idx from df. Is there way to do this in fewer lines compared to:

import pandas as pd

df = pd.DataFrame()
new_df = pd.DataFrame()


for i in range(n):
    new_df.loc[i] = df.iloc[idx]

thanks

Answer 1

You can use repeat:

N = 5
new_df = df.loc[df.index.repeat(N)]
# or for a particular row idx
new_df = df.loc[df.loc[idx].index.repeat(N)]

Or, for a new index reset_index with drop=True:

new_df = df.loc[df.index.repeat(N)].reset_index(drop=True)
# or for a particular row idx
new_df = df.loc[df.loc[idx].index.repeat(N)].reset_index(drop=True)

NB. if you have many rows in the input and only want to repeat one or some. replace df.index.repeat(N) with df.loc[idx].index.repeat(N) of df.loc[['idx1', 'idx2', 'idx3']].index.repeat(N)

Example input:

df = pd.DataFrame([['A', 'B', 'C']])

Output:

   0  1  2
0  A  B  C
1  A  B  C
2  A  B  C
3  A  B  C
4  A  B  C