Create a new column based on existing ones

import pandas as pd
import numpy as np

df = pd.DataFrame(["STD, City    State",
                   "33, Kolkata    West Bengal",
                   "44, Chennai    Tamil Nadu",
                   "40, Hyderabad    Telengana",
                   "80, Bangalore    Karnataka"], columns=['row'])
df

	row
0	STD, City State
1	33, Kolkata West Bengal
2	44, Chennai Tamil Nadu
3	40, Hyderabad Telengana
4	80, Bangalore Karnataka

split a column into two

df = df['row'].str.split(',', expand=True)
df

	0	1
0	STD	City State
1	33	Kolkata West Bengal
2	44	Chennai Tamil Nadu
3	40	Hyderabad Telengana
4	80	Bangalore Karnataka

make a column based on an exisitng one where its values are shifted by one row

df[2] = df[0].shift(-1) #shifted up
df[3] = df[0].shift(1) #shifted down
df

	0	1	2	3
0	STD	City State	33	NaN
1	33	Kolkata West Bengal	44	STD
2	44	Chennai Tamil Nadu	40	33
3	40	Hyderabad Telengana	80	44
4	80	Bangalore Karnataka	NaN	40

make a column based on a condition on another column

df[4] = np.where(df[2].fillna(0).astype(int) < 40, 'low', 'high')
df

	0	1	2	3	4
0	STD	City State	33	NaN	low
1	33	Kolkata West Bengal	44	STD	high
2	44	Chennai Tamil Nadu	40	33	high
3	40	Hyderabad Telengana	80	44	high
4	80	Bangalore Karnataka	NaN	40	low