just select 3 columns from dataframe pandas code example

Example 1: how to pick out separate columns from the pandas dataframe object

df1 = df.iloc[:, 0:2] # If you want to do it by index. Remember that Python does not slice inclusive of the ending index.
df1 = df[['a', 'b']] ## if you want to do it b nae

Example 2: df only take 2 columns

df1 = df[['a', 'b']]