1>>> import numpy as np
2>>> import pandas as pd
3>>> df = pd.DataFrame({"A": [1,2,3], "B": [2,3,4]})
4>>> df
5 A B
60 1 2
71 2 3
82 3 4
9>>> df["C"] = ""
10>>> df["D"] = np.nan
11>>> df
12 A B C D
130 1 2 NaN
141 2 3 NaN
152 3 4 NaN