df_catagorical=df.select_dtypes(include=['category'])
dfName.select_dtypes(include=['object']).columns.tolist()
df = pd.DataFrame({'vertebrates': ['Bird', 'Bird', 'Mammal', 'Fish', 'Amphibian', 'Reptile', 'Mammal']})
df.vertebrates.astype("category").cat.codes
nominal_attr = df.select_dtypes(include='category').columns
how to select pandas dataframe with categorical datatype