机器学习实战之K近邻

来源:互联网 发布:linux squid 透明代理 编辑:程序博客网 时间:2024/06/04 22:34
from numpy import *import operatorfrom cProfile import labelimport matplotlibimport matplotlib.pyplot as pltfrom os import listdirdef createDataSet():    group = array([1.0,1.1],[1.0,1.0],[0,0],[0,0.1])    labels = ['A','A','B','B']    return group, labelsdef 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]def TestClassify0():    group,labels = createDataSet()    classify0([0,0], group, labels, 3)    def file2matrix(filename):    fr = open(filename)    arrayOLines = fr.readlines()    numberOfLines = len(arrayOLines)    returnMat = zeros((numberOfLines,3))    classLabelVector = []    index = 0    for line in arrayOLines:        line = line.strip()        listFromLine = line.split('\t')        returnMat[index,:]=listFromLine[0:3]        classLabelVector.append(int(listFromLine[-1]))        index += 1    return returnMat,classLabelVector    def autoNorm(dataSet):    minVals = dataSet.min(0)    maxVals = dataSet.max(0)    ranges = maxVals - minVals    normDataSet = zeros(shape(dataSet))    m = dataSet.shape[0]    normDataSet = dataSet - tile(minVals,(m,1))    normDataSet = normDataSet/tile(ranges,(m,1))    return normDataSet, ranges, minValsdef Test():    datingDataMat,datingLabels = file2matrix('datingTestSet2.txt')# #     print datingDataMat,dataingLabels
#     display as scatter#     datingLabels2 = list(datingLabels)#     datingLabels2[:100] = [4]*100#     fig = plt.figure()#     ax = fig.add_subplot(1,1,1)#     ax.scatter(datingDataMat[:,1],datingDataMat[:,2],15.0*array(datingLabels),15.0*array(datingLabels))#     plt.show()    normMat, ranges, minVals = autoNorm(datingDataMat)    print normMat    def datingClassTest():    hoRatio = 0.50    datingDataMat, datingLabels = file2matrix('datingTestSet2.txt')    normMat, ranges, minVals = autoNorm(datingDataMat)    m = normMat.shape[0]    numTestVecs = int(m*hoRatio)    errorCount = 0.0    for i in range(numTestVecs):        classifierResult = classify0(normMat[i,:], normMat[numTestVecs:m,:], datingLabels[numTestVecs:m], 3)        print "the classifier came back with: %d, the real answer is: %d" % (classifierResult,datingLabels[i])        if (classifierResult != datingLabels[i]): errorCount += 1    print "the total error rate is: %f" % (errorCount/float(numTestVecs))    print errorCountdef img2vector(filename):    returnVect = zeros((1,1024))     fr = open(filename)    for i in range(32):        lineStr = fr.readline()        for j in range(32):            returnVect[0,32*i+j] = int(lineStr[j])    return returnVectdef testImg():     testVector = img2vector('trainingDigits/0_0.txt')    print testVector[0,0:31]    def handwriteingClassTest():    hwLabels = []    trainingFileList = listdir('trainingDigits')    m = len(trainingFileList)    trainingMat = zeros((m,1024))    for i in range(m):        fileNameStr = trainingFileList[i]        fileStr = fileNameStr.split('.')[0]        classNumStr = int(fileStr.split('_')[0])        hwLabels.append(classNumStr)        trainingMat[i,:] = img2vector('trainingDigits/%s' % fileNameStr)        testFileList = listdir('testDigits')    errorCount = 0.0    mTest = len(testFileList)    for i in range(mTest):        fileNameStr = testFileList[i]        fileStr = fileNameStr.split('.')[0]        classNumStr = int(fileStr.split('_')[0])        vectorUnderTest = img2vector('testDigits/%s' % fileNameStr)        classifierResult = classify0(vectorUnderTest, trainingMat, hwLabels, 3)        print "the classifier came back with: %d, the real answer is: %d" % (classifierResult,classNumStr)        if (classifierResult != classNumStr): errorCount += 1        print "\nthe total number of errors is: %d" % errorCount    print "\nthe total error rate is: %f" % (errorCount/float(mTest))if __name__ == '__main__':    handwriteingClassTest()