Python机器学习手册：从数据预处理到深度学习

266

｜

第

16

章

逻辑回归

们在

15.1

节中看到的那个逻辑函数被一个

softmax

函数替换 ：

16.2 Training a Multiclass Classier

Problem

Given more than two classes, you need to train a classifier model.

Solution

Train a logistic regression in scikit-learn with LogisticRegression using one-vs-rest

or multinomial methods:

# Load libraries

from sklearn.linear_model import LogisticRegression

from sklearn import datasets

from sklearn.preprocessing import StandardScaler

# Load data

iris = datasets.load_iris()

features = iris.data

target = iris.target

# Standardize features

scaler = StandardScaler()

features_standardized = scaler.fit_transform(features)

# Create one-vs-rest logistic regression object

logistic_regression ...