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Python 中的线性分类器

Michael (Mike) Gelbart

Instructor, The University of British Columbia

预备知识

本课程假定你已具备以下基础：

import sklearn.datasets

newsgroups = sklearn.datasets.fetch_20newsgroups_vectorized()

X, y = newsgroups.data, newsgroups.target

X.shape

(11314, 130107)

y.shape

(11314,)

from sklearn.neighbors import KNeighborsClassifier

knn = KNeighborsClassifier(n_neighbors=1)

knn.fit(X,y)

y_pred = knn.predict(X)

knn.score(X,y)

0.99991

from sklearn.model_selection import train_test_split

X_train, X_test, y_train, y_test = train_test_split(X, y)

knn.fit(X_train, y_train)

knn.score(X_test, y_test)

0.66242

Python 中的线性分类器