‘‘‘
Created?on?Sep?16?2010
kNN:?k?Nearest?Neighbors

Input:??????inX:?vector?to?compare?to?existing?dataset?（1xN）
????????????dataSet:?size?m?data?set?of?known?vectors?（NxM）
????????????labels:?data?set?labels?（1xM?vector）
????????????k:?number?of?neighbors?to?use?for?comparison?（should?be?an?odd?number）

Output:?????the?most?popular?class?label

@author:?pbharrin
‘‘‘
import?numpy?as?np
import?operator
from?os?import?listdir

def?classify0（inX?dataSet?labels?k）:
????dataSetSize?=?dataSet.shape[0]
????diffMat?=?np.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.items（）?key=operator.itemgetter（1）?reverse=True）
????return?sortedClassCount[0][0]

def?createDataSet（）:
????group?=?np.array（[[1.0?1.1]?[1.0?1.0]?[0?0]?[0?0.1]]）
????labels?=?[‘A‘?‘A‘?‘B‘?‘B‘]
????return?group?labels

def?file2matrix（filename）:
????love_dictionary?=?{‘largeDoses‘:3?‘smallDoses‘:2?‘didntLike‘:1}
????fr?=?open（filename）
????arrayOLines?=?fr.readlines（）
????numberOfLines?=?len（arrayOLines）????????????#get?the?number?of?lines?in?the?file
????returnMat?=?np.zeros（（numberOfLines?3））????????#prepare?matrix?to?return
????classLabelVector?=?[]???????????????????????#prepare?labels?return
????index?=?0
????for?line?in?arrayOLines:
????????line?=?line.strip（）
????????listFromLine?=?line.split（‘\t‘）
????????returnMat[index?:]?=?listFromLine[0:3]
????????if（listFromLine[-1].isdigit（））:
????????????classLabelVector.append（int（listFromLine[-1]））
????????else:
????????????classLabelVector.append（love_dictionary.get（listFromLine[-1]））
????????index?+=?1
????return?returnMat?classLabelVector


def?autoNorm（dataSet）:
????minVals?=?dataSet.min（0）
????maxVals?=?dataSet.max（0）
????ranges?=?maxVals?-?minVals
????normDataSet?=?np.zeros（np.shape（dataSet））
????m?=?dataSet.shape[0]
????normDataSet?=?dataSet?-?np.tile（minVals?（m?1））
????normDataSet?=?normDataSet/np.tile（ranges?（m?1））???#element?wise?divide
????return?normDataSet?ranges?minVals

def?datingClassTest（）:
????hoRatio?=?0.50??????#hold?out?10%
????datingDataMat?datingLabels?=?file2matrix（‘datingTestSet2.txt‘）???????#load?data?setfrom?file
????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?+=?1.0
????print（“the?total?error?rate?is:?%f“?%?（errorCount?/?float（numTestVecs）））
????print（errorC

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\
?????文件????????1045??2017-12-25?12:43??machinelearninginaction3x-master\.gitignore
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\EXTRAS\
?????文件?????????514??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\EXTRAS\README.txt
?????文件????????1988??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\EXTRAS\createDist.py
?????文件????????2094??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\EXTRAS\createDist2.py
?????文件?????????557??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\EXTRAS\createFirstPlot.py
?????文件???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\EXTRAS\testSet.txt
?????文件?????????239??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\README.txt
?????文件???????34725??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\datingTestSet.txt
?????文件???????26067??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\datingTestSet2.txt
?????文件??????739988??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\digits.zip
?????文件????????5230??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\kNN.py
?????文件?????????600??2017-12-25?12:43??machinelearninginaction3x-master\Ch02\kNNTest.py
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch03\
?????文件??????????84??2017-12-25?12:43??machinelearninginaction3x-master\Ch03\classifierStorage.txt
?????文件?????????771??2017-12-25?12:43??machinelearninginaction3x-master\Ch03\lenses.txt
?????文件????????3848??2017-12-25?12:43??machinelearninginaction3x-master\Ch03\treePlotter.py
?????文件????????4021??2017-12-25?12:43??machinelearninginaction3x-master\Ch03\trees.py
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\EXTRAS\
?????文件?????????514??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\EXTRAS\README.txt
?????文件?????????928??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\EXTRAS\create2Normal.py
?????文件?????????445??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\EXTRAS\monoDemo.py
?????文件????????7250??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\bayes.py
?????文件???????15141??2017-12-25?12:43??machinelearninginaction3x-master\Ch04\email.zip
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch05\
?????目錄???????????0??2017-12-25?12:43??machinelearninginaction3x-master\Ch05\EXTRAS\
?????文件?????????514??2017-12-25?12:43??machinelearninginaction3x-master\Ch05\EXTRAS\README.txt
?????文件????????1233??2017-12-25?12:43??machinelearninginaction3x-master\Ch05\EXTRAS\plot2D.py
............此處省略111個文件信息