How to duplicate Python dataframe one by one?

Question

I have a pandas.DataFrame as follows:

df1 = 
    a    b
0   1    2
1   3    4

I\'d like to make this three times to become:

Answer 1

I do not know if it is more efficient than your loop, but it easy enough to construct as:

Code:

pd.concat([df] * 3).sort_index()

Test Code:

df = pd.DataFrame([[1, 2], [3, 4]], columns=list('ab'))
print(pd.concat([df] * 3).sort_index())

Results:

   a  b
0  1  2
0  1  2
0  1  2
1  3  4
1  3  4
1  3  4