sklearn 常用api（二）

sklearn 常用api（一）

• classifier/estimator（而不同于 transformer）

  • from sklearn.linear_model import LogisticRegression
  • from sklearn.tree import DecisionTreeClassifier
  • from sklearn.neighbors import KNeighborsClassifier

sklearn.base

>>> import sklearn
>>> dir(sklearn.base)

sklearn.cross_validation

cv: cross_validation，交叉验证

from sklearn.cross_validation import StratifiedKFold
from sklearn.cross_validation import KFold

StratifiedKFold 是改进升级版的 KFold 方法，两者实现上的区别，根据二者的接口便知，

class sklearn.cross_validation.KFold(n, n_folds=3, shuffle=False, random_state=None) # 一般取 n == len(y) # 也即根据长度进行split # 不考虑class distribution class sklearn.cross_validation.StratifiedKFold(y, n_folds=3, shuffle=False, random_state=None) 

DecisionTreeClassifier

from sklearn.tree import DecisionTreeClassifier

Decision Tree classifier 是不需要对 features 进行标准化（StandardScaler）的。