Combine and fill a Pandas Dataframe with the single row of another

December 22, 2022

If I have two dataframes:

df1:

df1 = pd.DataFrame({'A':[10,20,15,30,45], 'B':[17,33,23,10,12]})


    A   B
0  10  17
1  20  33
2  15  23
3  30  10
4  45  12

df2:

df2 = pd.DataFrame({'C':['cat'], 'D':['dog'], 'E':['emu'], 'F':['frog'], 'G':['goat'], 'H':['horse'], 'I':['iguana']})


     C    D    E     F     G      H       I
0  cat  dog  emu  frog  goat  horse  iguana

How do I combine the two dataframes and fill df1 whereby each row is a replicate of df2 ?

Here is what I have so far. The code works as intended, but if I were to have hundreds of columns, then I would anticipate there would be a much easier way than my current method:

Current Code:

df1 = df1.assign(C = lambda x: df2.C[0],
                 D = lambda x: df2.D[0],
                 E = lambda x: df2.E[0],
                 F = lambda x: df2.F[0],
                 G = lambda x: df2.G[0],
                 H = lambda x: df2.H[0],
                 I = lambda x: df2.I[0])

Expected output:

    A   B    C    D    E     F     G      H       I
0  10  17  cat  dog  emu  frog  goat  horse  iguana
1  20  33  cat  dog  emu  frog  goat  horse  iguana
2  15  23  cat  dog  emu  frog  goat  horse  iguana
3  30  10  cat  dog  emu  frog  goat  horse  iguana
4  45  12  cat  dog  emu  frog  goat  horse  iguana

>Solution :

Use DataFrame.assign with Series by first row:

df = df1.assign(**df2.iloc[0])
print (df)
    A   B    C    D    E     F     G      H       I
0  10  17  cat  dog  emu  frog  goat  horse  iguana
1  20  33  cat  dog  emu  frog  goat  horse  iguana
2  15  23  cat  dog  emu  frog  goat  horse  iguana
3  30  10  cat  dog  emu  frog  goat  horse  iguana
4  45  12  cat  dog  emu  frog  goat  horse  iguana