change column to in16 datatype astype pandas code example

Example 1: change dataframe column type

>>> df.astype({'col1': 'int32'}).dtypes
col1    int32
col2    int64
dtype: object

Example 2: set dtype for multiple columns pandas

import pandas as pd

df = pd.DataFrame({'id':['a1', 'a2', 'a3', 'a4'],
  				   'A':['0', '1', '2', '3'],
                   'B':['1', '1', '1', '1'],
                   'C':['0', '1', '1', '0']})

df[['A', 'B', 'C']] = df[['A', 'B', 'C']].apply(pd.to_numeric, axis = 1)