一、样例理解
feature_names = ['col1 ', 'col2', 'col3', 'col4', 'col5', 'col6']
values = np.random.randint(20, size=(10,6))
dataset = pd.DataFrame(data = values, columns = feature_names)
print("转换前的数据为\n",dataset)
print("======================================================")
feature_names = list(dataset)
print("特征名称为\n",feature_names)
for col in feature_names:
dataset[col] = dataset[col].astype('category',copy=False)
print("转换后的数据为\n",dataset)

二、dataframe格式数据样例说明
test1 = pd.read_csv('./test.csv',encoding='utf-8',index_col=0)

features = [x for x in test3.columns if x not in ['pos','LABEL']]
test2[col] = test2[col].astype('category',copy=False)
