How to assign values to multiple non existing columns in a pandas dataframe?

Question

So what I want to do is to add columns to a dataframe and fill them (all rows respectively) with a single value.

import pandas as pd
import numpy as np

df          


        

Answer 1

You can using assign and pass a dict in it

df.assign(**dict(zip(['C','D'],[arr.tolist()]*2)))
Out[755]: 
   A  B  C  D
0  1  2  7  7
1  3  4  8  8