Extracting specific selected columns to new DataFrame as a copy

Question

I have a pandas DataFrame with 4 columns and I want to create a new DataFrame that only has three of the columns. This question is similar

Answer 1

If you want to have a new data frame then:

import pandas as pd
old = pd.DataFrame({'A' : [4,5], 'B' : [10,20], 'C' : [100,50], 'D' : [-30,-50]})
new=  old[['A', 'C', 'D']]