‘‘‘
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
‘‘‘
from?numpy?import?*
import?operator
from?os?import?listdir

def?classify0（inX?dataSet?labels?k）:
????dataSetSize?=?dataSet.shape[0]
????diffMat?=?tile（inX?（dataSetSize1））?-?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（voteIlabel0）?+?1
????sortedClassCount?=?sorted（classCount.iteritems（）?key=operator.itemgetter（1）?reverse=True）
????return?sortedClassCount[0][0]

def?createDataSet（）:
????group?=?array（[[1.01.1][1.01.0][00][00.1]]）
????labels?=?[‘A‘‘A‘‘B‘‘B‘]
????return?group?labels

def?file2matrix（filename）:
????fr?=?open（filename）
????numberOfLines?=?len（fr.readlines（））?????????#get?the?number?of?lines?in?the?file
????returnMat?=?zeros（（numberOfLines3））????????#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?returnMatclassLabelVector
????
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?（m1））
????normDataSet?=?normDataSet/tile（ranges?（m1））???#element?wise?divide
????return?normDataSet?ranges?minVals
???
def?datingClassTest（）:
????hoRatio?=?0.50??????#hold?out?10%
????datingDataMatdatingLabels?=?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?errorCount
????
def?img2vector（filename）:
????returnVect?=?zeros（（11024））
????fr?=?open（filename）
????for?i?in?range（32）:
????????lineStr?=?fr.readline（）
????????for?j?in?range（32）:
????????????returnVect[032*i+j]?=?int（li

?屬性????????????大小?????日期????時間???名稱
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?????目錄???????????0??2018-04-02?16:47??machinelearninginaction\
?????目錄???????????0??2012-03-01?15:44??machinelearninginaction\.git\
?????文件??????????31??2012-03-01?15:44??machinelearninginaction\.git\COMMIT_EDITMSG
?????文件?????????341??2011-05-04?15:31??machinelearninginaction\.git\config
?????文件??????????73??2011-05-04?15:27??machinelearninginaction\.git\description
?????文件??????????23??2011-05-04?15:27??machinelearninginaction\.git\HEAD
?????目錄???????????0??2011-05-04?15:27??machinelearninginaction\.git\hooks\
?????文件?????????452??2011-05-04?15:27??machinelearninginaction\.git\hooks\applypatch-msg.sample
?????文件?????????896??2011-05-04?15:27??machinelearninginaction\.git\hooks\commit-msg.sample
?????文件?????????160??2011-05-04?15:27??machinelearninginaction\.git\hooks\post-commit.sample
?????文件?????????552??2011-05-04?15:27??machinelearninginaction\.git\hooks\post-receive.sample
?????文件?????????189??2011-05-04?15:27??machinelearninginaction\.git\hooks\post-update.sample
?????文件?????????398??2011-05-04?15:27??machinelearninginaction\.git\hooks\pre-applypatch.sample
?????文件????????1578??2011-05-04?15:27??machinelearninginaction\.git\hooks\pre-commit.sample
?????文件????????4951??2011-05-04?15:27??machinelearninginaction\.git\hooks\pre-rebase.sample
?????文件????????1239??2011-05-04?15:27??machinelearninginaction\.git\hooks\prepare-commit-msg.sample
?????文件????????3611??2011-05-04?15:27??machinelearninginaction\.git\hooks\update.sample
?????文件????????9112??2012-03-01?15:44??machinelearninginaction\.git\index
?????目錄???????????0??2011-05-04?15:27??machinelearninginaction\.git\info\
?????文件?????????240??2011-05-04?15:27??machinelearninginaction\.git\info\exclude
?????目錄???????????0??2011-05-04?15:30??machinelearninginaction\.git\logs\
?????文件????????7468??2012-03-01?15:44??machinelearninginaction\.git\logs\HEAD
?????目錄???????????0??2011-05-04?15:31??machinelearninginaction\.git\logs\refs\
?????目錄???????????0??2011-05-04?15:30??machinelearninginaction\.git\logs\refs\heads\
?????文件????????7468??2012-03-01?15:44??machinelearninginaction\.git\logs\refs\heads\master
?????目錄???????????0??2011-05-04?15:31??machinelearninginaction\.git\logs\refs\remotes\
?????目錄???????????0??2011-05-04?15:31??machinelearninginaction\.git\logs\refs\remotes\origin\
?????文件????????6480??2012-03-01?15:44??machinelearninginaction\.git\logs\refs\remotes\origin\master
?????目錄???????????0??2012-03-01?15:44??machinelearninginaction\.git\objects\
?????目錄???????????0??2011-12-19?17:28??machinelearninginaction\.git\objects\00\
?????文件?????????933??2011-12-19?17:28??machinelearninginaction\.git\objects\00\fdb1abb7c5be830ed09762c0d4d1559aeb5e41
............此處省略621個文件信息