If you’re sure the index row values are the same then to avoid the index alignment order then just call reset_index(), this will reset your index values back to start from 0:
df_c = pd.concat([df_a.reset_index(drop=True), df_b], axis=1)
If you’re sure the index row values are the same then to avoid the index alignment order then just call reset_index(), this will reset your index values back to start from 0:
df_c = pd.concat([df_a.reset_index(drop=True), df_b], axis=1)