the difference among pd.factorize, pd.get_dummies, sklearn.preprocessing.LableEncoder and OneHotE...
1.pd.factorize和sklearn.preprocessing.LableEncoder都只接受一维数组输入、一维数组输出;pd.get_dummies和sklean.preprocessing.OneHotEncoder可接受多维数组输入、多维输出;2.pd.factorize和sklearn.preprocessing.LableEncoder是编码,不一定搞成one-hot类型的,