‘‘‘
Created?on?Feb?16?2011
k?Means?Clustering?for?Ch10?of?Machine?Learning?in?Action
@author:?Peter?Harrington
‘‘‘
from?numpy?import?*

def?loadDataSet（fileName）:??????#general?function?to?parse?tab?-delimited?floats
????dataMat?=?[]????????????????#assume?last?column?is?target?value
????fr?=?open（fileName）
????for?line?in?fr.readlines（）:
????????curLine?=?line.strip（）.split（‘\t‘）
????????fltLine?=?map（floatcurLine）?#map?all?elements?to?float（）
????????dataMat.append（fltLine）
????return?dataMat

def?distEclud（vecA?vecB）:
????return?sqrt（sum（power（vecA?-?vecB?2）））?#la.norm（vecA-vecB）

def?randCent（dataSet?k）:
????n?=?shape（dataSet）[1]
????centroids?=?mat（zeros（（kn）））#create?centroid?mat
????for?j?in?range（n）:#create?random?cluster?centers?within?bounds?of?each?dimension
????????minJ?=?min（dataSet[:j]）?
????????rangeJ?=?float（max（dataSet[:j]）?-?minJ）
????????centroids[:j]?=?mat（minJ?+?rangeJ?*?random.rand（k1））
????return?centroids
????
def?kMeans（dataSet?k?distMeas=distEclud?createCent=randCent）:
????m?=?shape（dataSet）[0]
????clusterAssment?=?mat（zeros（（m2）））#create?mat?to?assign?data?points?
??????????????????????????????????????#to?a?centroid?also?holds?SE?of?each?point
????centroids?=?createCent（dataSet?k）
????clusterChanged?=?True
????while?clusterChanged:
????????clusterChanged?=?False
????????for?i?in?range（m）:#for?each?data?point?assign?it?to?the?closest?centroid
????????????minDist?=?inf;?minIndex?=?-1
????????????for?j?in?range（k）:
????????????????distJI?=?distMeas（centroids[j:]dataSet[i:]）
????????????????if?distJI?????????????????????minDist?=?distJI;?minIndex?=?j
????????????if?clusterAssment[i0]?!=?minIndex:?clusterChanged?=?True
????????????clusterAssment[i:]?=?minIndexminDist**2
????????print?centroids
????????for?cent?in?range（k）:#recalculate?centroids
????????????ptsInClust?=?dataSet[nonzero（clusterAssment[:0].A==cent）[0]]#get?all?the?point?in?this?cluster
????????????centroids[cent:]?=?mean（ptsInClust?axis=0）?#assign?centroid?to?mean?
????return?centroids?clusterAssment

def?biKmeans（dataSet?k?distMeas=distEclud）:
????m?=?shape（dataSet）[0]
????clusterAssment?=?mat（zeros（（m2）））
????centroid0?=?mean（dataSet?axis=0）.tolist（）[0]
????centList?=[centroid0]?#create?a?list?with?one?centroid
????for?j?in?range（m）:#calc?initial?Error
????????clusterAssment[j1]?=?distMeas（mat（centroid0）?dataSet[j:]）**2
????while?（len（centList）?????????lowestSSE?=?inf
????????for?i?in?range（len（centList））:
????????????ptsInCurrCluster?=?dataSet[nonzero（clusterAssment[:0].A==i）[0]:]#get?the?data?points?currently?in?cluster?i
????????????centroidMat?splitClustAss?=?kMeans（ptsInCurrCluster?2?distMeas）
????????????sseSplit?=?sum（splitClustAss[:1]）#compare?the?SSE?to?the?currrent?minimum
????????????sseNotSplit?=?sum（clusterAssment[nonzero（clusterAssment[:0].A!=i）[0]1]）
????????????print?“sseSplit?and?notSplit:?“sseSplitsseNotSplit
???????

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2011-12-28?15:30??Ch10\
?????文件????????3105??2011-03-17?21:17??Ch10\portlandClubs.txt
?????目錄???????????0??2020-11-16?01:04??__MACOSX\
?????目錄???????????0??2020-11-16?01:04??__MACOSX\Ch10\
?????文件?????????222??2011-03-17?21:17??__MACOSX\Ch10\._portlandClubs.txt
?????文件??????459112??2011-03-18?12:00??Ch10\Portland.png
?????文件?????????222??2011-03-18?12:00??__MACOSX\Ch10\._Portland.png
?????文件????????6397??2011-12-28?15:30??Ch10\kMeans.pyc
?????文件?????????222??2011-12-28?15:30??__MACOSX\Ch10\._kMeans.pyc
?????文件????????1600??2011-03-15?13:03??Ch10\testSet.txt
?????文件?????????222??2011-03-15?13:03??__MACOSX\Ch10\._testSet.txt
?????文件????????6419??2011-12-28?15:52??Ch10\kMeans.py
?????文件?????????222??2011-12-28?15:52??__MACOSX\Ch10\._kMeans.py
?????文件????????1194??2011-03-16?10:16??Ch10\testSet2.txt
?????文件?????????222??2011-03-16?10:16??__MACOSX\Ch10\._testSet2.txt
?????文件????????4693??2011-03-18?09:56??Ch10\places.txt
?????文件?????????222??2011-03-18?09:56??__MACOSX\Ch10\._places.txt
?????文件?????????222??2011-12-28?15:30??__MACOSX\._Ch10