程序清单2-6 手写数字识别系统的测试代码
伪代码
- def img2vector(filename):#返回1*1024行向量
- returnVect = zeros((1,1024))
- fr = open(filename)
- for i in range(32):
- #一次只读一行
- lineStr = fr.readline()
- for j in range(32):
- #行复制
- returnVect[0,32*i+j] = int(lineStr[j])
- return returnVect
- def handwritingClassTest():
- hwLabels = []
- # listdir 可以列出trainingDigits文件夹目录中的文件
- trainingFileList = listdir('trainingDigits') #load the training set
- #check the len of trainingFileList
- m = len(trainingFileList)
- #每行数据存储一个图像
- trainingMat = zeros((m,1024))
- for i in range(m):
- #get one name of trainingFileList,ex:0_17.txt
- fileNameStr = trainingFileList[i]
- #get"0_17";
- fileStr = fileNameStr.split('.')[0] #split函数,去除'.',然后将剩余两侧元素分为一行二列的
- #向量,然后[0]得到第一列,即0_17
- #get"0"
- classNumStr = int(fileStr.split('_')[0])
- hwLabels.append(classNumStr)
- trainingMat[i,:] = img2vector('trainingDigits/%s' % fileNameStr)
- testFileList = listdir('testDigits') #iterate through the test set
- errorCount = 0.0
- mTest = len(testFileList)
- for i in range(mTest):
- #以下为对测试数据的相同处理
- fileNameStr = testFileList[i]
- fileStr = fileNameStr.split('.')[0] #take off .txt
- classNumStr = int(fileStr.split('_')[0])
- vectorUnderTest = img2vector('testDigits/%s' % fileNameStr)
- #k近邻算法
- classifierResult = classify0(vectorUnderTest, trainingMat, hwLabels, 3)
- #算法输出与结果比较
- print("the classifier came back with: %d, the real answer is\
- : %d" % (classifierResult, classNumStr))
- if (classifierResult != classNumStr): errorCount += 1.0
- print ("\nthe total number of errors is: %d" % errorCount)
- print( "\nthe total error rate is: %f" % (errorCount/float(mTest)))
完整代码
- #批量注释、批量取消注释 Ctrl+/
- # from __future__ import print_function
- from numpy import *
- from os import listdir
- import operator#运算符模块
- import matplotlib.pyplot as plt
- 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
- group,labels=createDataSet()
- def classify0(inX, dataSet, labels, k): #inX: 待测试数据 ; dataSet: 训练样本集;labels: 样本集的标签;k近邻
- dataSetSize = dataSet.shape[0] #to get the rows of the matrix
- # to get the Xi-Yi of the dataSet
- diffMat = tile(inX, (dataSetSize,1)) - dataSet #a=[1 2],b=[2 3];tile(a,b) to generate 2*3 matrix when
- #the element all is a [1 2]
- sqDiffMat = diffMat**2
- sqDistances = sqDiffMat.sum(axis=1) #使每行的元素相加,得到测试样本与各训练样本distance**2
- #axis=0,按列相加;axis=1,按行相加;
- distances = sqDistances**0.5
- sortedDistIndicies = distances.argsort() #将distance中的元素从小到大排列,
- # 提取其对应的index(索引),然后输出到 sortedDistIndicies
- #声明一个dict:{key:value1,key2:value2}
- classCount={}
- for i in range(k):
- voteIlabel = labels[sortedDistIndicies[i]]
- #classCount= {'B': 2, 'A': 1},初始化后,classCount每得到一个相同的voteIlabel,就+1
- classCount[voteIlabel] = classCount.get(voteIlabel,0) + 1 #当我们获取字典里的值的时候,一个是通过
- # 键值对,即dict['key'],另一个就是dict.get()方法
- # dict.get(voteIlabel,0) = 0, 此处0 to be initiated,
- # 之后就没有作用了。
- #items方法是可以将字典中的所有项,以列表方式返回。 iteritems方法与items方法相比作用大致相同,只是它的返回值不是列表,而是一个迭代器
- #Python3 中没有iteritems函数,需要用values()代替,并用list转为列表
- # sortedClassCount = sorted((key_label, value_num), key=operator.itemgetter(1), reverse=True)
- #python3中无法使用iteritems,需要对上面这句话改造,我们通过得到两个list,得到出现频率最高的label
- key_label=list(classCount.keys())
- value_num=list(classCount.values())
- #label出现频率由小到大排列,并返回索引index
- sortedvalue_num_indicies = argsort(value_num)
- #返回频率最大的label
- return key_label[len(sortedvalue_num_indicies)-1]
- # group,labels = createDataSet()
- # a=classify0([0,0], group,labels,3)
- # print(a)
- #自己根据Python3 改正后的函数
- # def file2matrix(filename): # 将数据分离为样本数据与标签
- # #open a file, default: 'r'ead
- # fr = open(filename)
- # #一次读取所有行
- # arrayOLines = fr.readlines()
- # #得到行数
- # numberOfLines = len(arrayOLines)
- # #1000*3 zeros matrix,row-1000, column-3
- # returnMat = zeros((numberOfLines,3))
- # #声明
- # classLabelVector = []
- # classLabelVector_Value = []
- # index = 0
- # #逐行扫描
- # for line in arrayOLines:
- # #strip函数会删除头和尾的字符,中间的不会删除
- # line = line.strip()
- # #删除‘\t’字符,仅剩下数据,供使用
- # listFromLine = line.split('\t')
- # #得到前三列数据,即飞行时间,游戏,冰激凌
- # returnMat[index, :] = listFromLine[0:3]
- # #得到largeDoses,smallDoses,didntLike的label
- # classLabelVector.append(listFromLine[-1]) #无法将largeDoses,smallDoses,didntLike
- # #转换为int。基于这个思想,我们在这里将得到的行矩阵建立
- # #一个数值矩阵与之对应,暂时这样处理,不合适再继续修改
- # if classLabelVector[index] == 'largeDoses':
- # classLabelVector_Value.append(3)
- # elif classLabelVector[index] == 'smallDoses':
- # classLabelVector_Value.append(2)
- # else:
- # classLabelVector_Value.append(1)
- # index += 1
- # return returnMat, classLabelVector_Value
- def file2matrix(filename):
- fr = open(filename)
- numberOfLines = len(fr.readlines()) #get the number of lines in the file
- returnMat = zeros((numberOfLines,3)) #prepare matrix to return
- classLabelVector = [] #prepare labels return
- fr = open(filename)
- index = 0
- for line in fr.readlines():
- 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):#得到归一化后的数据样本,最大值最小值之差,与最小值
- #得到每一列的max,min
- minVals = dataSet.min(0)
- maxVals = dataSet.max(0)
- ranges = maxVals - minVals
- #initiate a zero-matrix like dataSet's shape
- normDataSet = zeros(shape(dataSet))
- #get the num of row in dataSet
- m = dataSet.shape[0]
- #init a matrix of minvals that the same rows to the dataSet, 从而使当前数据矩阵中的每个数减去最小值
- normDataSet = dataSet - tile(minVals, (m,1)) #tile(matrixlike,A) :init a matrix when the shape is same to A
- #meanwhile, if A is a number, the matrix is A*1, if A is (m,n),the matrix
- #is m*n matrix
- normDataSet = normDataSet/tile(ranges, (m,1)) #element wise divide
- return normDataSet, ranges, minVals
- def datingClassTest():
- #使用10%的数据去测试分类器
- hoRatio = 0.10 # hold out 10%
- #datingTestSet2.txt中标签全部变为3,2,1,而不是字符串label,所以如果不想改file2matrix()函数,应用datingTestSet.txt
- #如果file2matrix()用书中原程序,可用datingTestSet.txt
- datingDataMat, datingLabels = file2matrix('datingTestSet.txt') # 将数据分离为样本数据与标签
- normMat, ranges, minVals = autoNorm(datingDataMat)#得到归一化后的数据样本,最大值最小值之差,与最小值
- #get the num of the row
- m = normMat.shape[0]
- #get the test num of normMat
- numTestVecs = int(m * hoRatio)
- errorCount = 0.0
- for i in range(numTestVecs):
- #数据前numTestVecs个为测试数据,以后为样本训练集
- classifierResult = classify0(normMat[i, :], normMat[numTestVecs:m, :], datingLabels[numTestVecs:m], 3) # inX: 待测试数据 ; dataSet: 训练样本集;labels: 样本集的标签;k近邻
- #测试结果与真正结果对照输出
- print("the classifier came back with: %d, the real answer is: %d" % (classifierResult, datingLabels[i]))
- if classifierResult != datingLabels[i]:
- errorCount += 1.0
- print("the total error rate is: %f"% (errorCount / float(numTestVecs)))
- print(errorCount)
- def img2vector(filename):#返回1*1024行向量
- returnVect = zeros((1,1024))
- fr = open(filename)
- for i in range(32):
- #一次只读一行
- lineStr = fr.readline()
- for j in range(32):
- #行复制
- returnVect[0,32*i+j] = int(lineStr[j])
- return returnVect
- def handwritingClassTest():
- hwLabels = []
- # listdir 可以列出trainingDigits文件夹目录中的文件
- trainingFileList = listdir('trainingDigits') #load the training set
- #check the len of trainingFileList
- m = len(trainingFileList)
- #每行数据存储一个图像
- trainingMat = zeros((m,1024))
- for i in range(m):
- #get one name of trainingFileList,ex:0_17.txt
- fileNameStr = trainingFileList[i]
- #get"0_17";
- fileStr = fileNameStr.split('.')[0] #split函数,去除'.',然后将剩余两侧元素分为一行二列的
- #向量,然后[0]得到第一列,即0_17
- #get"0"
- classNumStr = int(fileStr.split('_')[0])
- hwLabels.append(classNumStr)
- trainingMat[i,:] = img2vector('trainingDigits/%s' % fileNameStr)
- testFileList = listdir('testDigits') #iterate through the test set
- errorCount = 0.0
- mTest = len(testFileList)
- for i in range(mTest):
- #以下为对测试数据的相同处理
- fileNameStr = testFileList[i]
- fileStr = fileNameStr.split('.')[0] #take off .txt
- classNumStr = int(fileStr.split('_')[0])
- vectorUnderTest = img2vector('testDigits/%s' % fileNameStr)
- #k近邻算法
- classifierResult = classify0(vectorUnderTest, trainingMat, hwLabels, 3)
- #算法输出与结果比较
- print("the classifier came back with: %d, the real answer is\
- : %d" % (classifierResult, classNumStr))
- if (classifierResult != classNumStr): errorCount += 1.0
- print ("\nthe total number of errors is: %d" % errorCount)
- print( "\nthe total error rate is: %f" % (errorCount/float(mTest)))
测试
- handwritingClassTest()
完成!
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转自:https://blog.youkuaiyun.com/shunquanlan9446/article/details/79779403