2.2sklearn.preprocessing.PolynomialFeatures生成交叉特征
阿新 • • 發佈:2018-10-07
inter 交叉 roc 標識 mod lse 參數說明 python range
sklearn.preprocessing.PolynomialFeatures原文
多項式生成函數:sklearn.preprocessing.PolynomialFeatures(degree=2, interaction_only=False, include_bias=True)
參數說明:
degree
:默認為2,多項式次數(就同幾元幾次方程中的次數一樣)interaction_only
:是否包含單個自變量**n(n>1)特征數據標識,默認為False,為True則表示去除與自己相乘的情況include_bias
:是否包含偏差標識,默認為True,為False則表示不包含偏差項
import numpy as np
from sklearn.preprocessing import PolynomialFeatures
X = np.arange(6).reshape(3, 2)
X
array([[0, 1],
[2, 3],
[4, 5]])
poly = PolynomialFeatures(degree = 2)
poly.fit_transform(X)
array([[ 1., 0., 1., 0., 0., 1.], [ 1., 2., 3., 4., 6., 9.], [ 1., 4., 5., 16., 20., 25.]])
# 設置參數interaction_only = True,不包含單個自變量****n(n>1)特征數據
poly = PolynomialFeatures(degree = 2, interaction_only = True)
poly.fit_transform(X)
array([[ 1., 0., 1., 0.],
[ 1., 2., 3., 6.],
[ 1., 4., 5., 20.]])
# 再添加 設置參數include_bias= False,不包含偏差項數據 poly = PolynomialFeatures(degree = 2, interaction_only = True, include_bias=False)
poly.fit_transform(X)
array([[ 0., 1., 0.],
[ 2., 3., 6.],
[ 4., 5., 20.]])
2.2sklearn.preprocessing.PolynomialFeatures生成交叉特征