• 1000 1008 *
with open("out.csv","wb") as f:
f.write("\n".join([df1.to_csv(),df2.to_csv()])
print("".join([df1.to_csv(), df2.to_csv()]))
"""
,A,B
0,1,2
1,2,3
2,3,4
,C,D
0,3,4
1,4,5
"""
вот версия Excel ...
with pandas.ExcelWriter("out.xlsx") as w:
df1.to_excel(w)
df2.to_excel(w,startrow=len(df1)+1)