机器学习实战knn

Posted 2020-08-22 数仙据灵

最近在学习这本书，按照书上的实例编写了knn.py的文件，使用canopy进行编辑，用shell交互时发现运行时报错：

>>> kNN.classify0([0,0],group,labels,3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name ‘kNN‘ is not defined

　　运行的代码如下：

from numpy import *  
import operator  
   
def createDataSet():  
    group = array([[1.0,1.1],[1.0,1.0],[0,0],[0,0.1]])  
    labels = [‘A‘,‘A‘,‘B‘,‘B‘]  
    return group,labels  
  
def classify0(inX,dataSet,labels,k):  
    dataSetSize = dataSet.shape[0]  
    diffMat = tile(inX,(dataSetSize,1)) - dataSet  
    sqDiffMat = diffMat**2  
    sqDistances = sqDiffMat.sum(axis = 1)  
    distances = sqDistances**0.5  
    sortedDistIndicies = distances.argsort()  
    classCount = {}  
    for i in range(k):  
        voteIlabel = labels[sortedDistIndicies[i]]  
        classCount[voteIlabel] = classCount.get(voteIlabel,0) + 1  
    sortedClassCount = sorted(classCount.iteritems(),  
                              key=operator.itemgetter(1),reverse=True)  
    return sortedClassCount[0][0]  

然后我在canopy中重新关闭程序，又打开后，就可以运行成功了

import kNN

group,labels=kNN.createDataSet()

kNN.classify0([0,0],group,labels,3)

还有一点是文件名不识别大小写 需要注意