sklearn學習筆記之knn分類演算法
阿新 • • 發佈:2018-12-15
# -*- coding: utf-8 -*- import sklearn from sklearn import neighbors import matplotlib.pyplot as plt from sklearn.model_selection import train_test_split from sklearn import datasets import pandas as pd import numpy def getData_1(): iris = datasets.load_iris() X = iris.data #樣本特徵矩陣,150*4矩陣,每行一個樣本,每個樣本維度是4y = iris.target #樣本類別矩陣,150維行向量,每個元素代表一個樣本的類別 df1=pd.DataFrame(X, columns =['SepalLengthCm','SepalWidthCm','PetalLengthCm','PetalWidthCm']) df1['target']=y return df1 df=getData_1() X_train, X_test, y_train, y_test = train_test_split(df.iloc[:,0:3],df['target'], test_size=0.3, random_state=42) print X_train, X_test, y_train, y_test model = neighbors.KNeighborsClassifier(n_neighbors=5, n_jobs=1) # knn """引數 --- n_neighbors: 使用鄰居的數目 n_jobs:並行任務數 """ model.fit(X_train,y_train) predict=model.predict(X_test) print predict print y_test.values
print 'knn分類:{:.3f}'.format(model.score(X_test, y_test))
結果:
預測值:[2 0 2 1 1 0 1 1 1 1 2 0 0 0 0 1 2 1 1 2 0 2 0 2 2 2 2 2 0 0 0 0 1 0 0 2 1 0 0 0 2 1 1 0 0] 真實值:[1 0 2 1 1 0 1 2 1 1 2 0 0 0 0 1 2 1 1 2 0 2 0 2 2 2 2 2 0 0 0 0 1 0 0 2 1 0 0 0 2 1 1 0 0] knn分類準確度:0.956