利用Python實現樸素貝葉斯文字分類
阿新 • • 發佈:2019-01-09
Python是一種面向物件、解釋型計算機程式設計語,作者是Guido
van Rossum(吉多·範羅蘇姆),1991年公開正式發行。粗糙進行歸納:
(1)Python是純粹自由軟體,原始碼和直譯器CPython遵循 GPL協議
(2)Python語法簡潔清晰
(3)Python具有豐富和強大的庫(^_^膠水語言^_^)
NumPy系統是Python的一種開源的數值計算擴充套件,一個用python實現的科學計算包。這種工具可用來儲存和處理大型矩陣。
(1)下載對應Python版本的NumPy(請用Ctrl+F查詢numpy)
http://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy
(2)將.whl改為.rar
(3)將.rar中的內容全部Copy到Python安裝目錄下的.\Lib\site-packages之下。例如: D:\Program Files\python\Lib\site-packages Until to here, we can use it. Ok, Let's see an example about Naive Bayesian Network and itsAlgorithm. 1)Naive Bayesian Network 2)Naive Bayesian Algorithm
3)I will give some net-source to you http://scikit-learn.org/stable/modules/naive_bayes.html http://www.saedsayad.com/naive_bayesian.htm http://www.saedsayad.com/naive_bayesian_exercise.htm http://www.saedsayad.com/flash/Bayesian.html Step to here, we already have prepared Programming Language, Tool of NumPy, Naive Bayesian Network and Algorithm. So, let's implement Naive Baysian Classifier by this Language & Tool &Theory.Fellow is Code-Programming, ^_^let's see it now.
1)Some Code of Python-Self-Methods about Naive Bayesian and save it as bayes.py.
''' Created on Oct 19, 2010 ''' #匯入numpy(一種開源的數值計算擴充套件,可用來儲存和處理大型矩陣) from numpy import * def loadDataSet(): postingList=[ [ 'my', 'dog', 'has', 'flea', 'problems', 'help', 'please' ], [ 'maybe', 'not', 'take', 'him', 'to', 'dog', 'park', 'stupid' ], [ 'my', 'dalmation', 'is', 'so', 'cute', 'I', 'love', 'him' ], [ 'stop', 'posting', 'stupid', 'worthless', 'garbage' ], [ 'mr', 'licks', 'ate', 'my', 'steak', 'how', 'to', 'stop', 'him' ], [ 'quit', 'buying', 'worthless', 'dog', 'food', 'stupid' ] ] classVec = [ 0,1,0,1,0,1 ] #1 is abusive, 0 not return postingList,classVec def createVocabList(dataSet): vocabSet = set([ ]) #create empty set for document in dataSet: vocabSet = vocabSet | set(document) #union of the two sets return list(vocabSet) def setOfWords2Vec(vocabList, inputSet): returnVec = [ 0 ]*len(vocabList) for word in inputSet: if word in vocabList: returnVec[ vocabList.index(word) ] = 1 else: print (("the word: %s is not in my Vocabulary!" % word)) return returnVec def trainNB0(trainMatrix,trainCategory): numTrainDocs = len(trainMatrix) numWords = len(trainMatrix[ 0 ]) pAbusive = sum(trainCategory)/float(numTrainDocs) p0Num = ones(numWords); p1Num = ones(numWords) #change to ones() p0Denom = 2.0; p1Denom = 2.0 #change to 2.0 for i in range(numTrainDocs): if trainCategory[ i ] == 1: p1Num += trainMatrix[ i ] p1Denom += sum(trainMatrix[ i ]) else: p0Num += trainMatrix[ i ] p0Denom += sum(trainMatrix[ i ]) p1Vect = log(p1Num/p1Denom) #change to log() p0Vect = log(p0Num/p0Denom) #change to log() return p0Vect,p1Vect,pAbusive def classifyNB(vec2Classify, p0Vec, p1Vec, pClass1): p1 = sum(vec2Classify * p1Vec) + log(pClass1) #element-wise mult p0 = sum(vec2Classify * p0Vec) + log(1.0 - pClass1) if p1 > p0: return 1 else: return 0 def bagOfWords2VecMN(vocabList, inputSet): returnVec = [ 0 ]*len(vocabList) for word in inputSet: if word in vocabList: returnVec[ vocabList.index(word) ] += 1 return returnVec def testingNB(): listOPosts,listClasses = loadDataSet() myVocabList = createVocabList(listOPosts) trainMat=[ ] for postinDoc in listOPosts: trainMat.append(setOfWords2Vec(myVocabList, postinDoc)) p0V,p1V,pAb = trainNB0(array(trainMat),array(listClasses)) testEntry = [ 'love', 'my', 'dalmation' ] thisDoc = array(setOfWords2Vec(myVocabList, testEntry)) print ((testEntry,'classified as: ',classifyNB(thisDoc,p0V,p1V,pAb))) testEntry = [ 'stupid', 'garbage' ] thisDoc = array(setOfWords2Vec(myVocabList, testEntry)) print ((testEntry,'classified as: ',classifyNB(thisDoc,p0V,p1V,pAb))) def textParse(bigString): #input is big string, #output is word list import re listOfTokens = re.split(r'\W*', bigString) return [ tok.lower() for tok in listOfTokens if len(tok) > 2 ] def spamTest(): docList=[ ]; classList = [ ]; fullText =[ ] for i in range(1,26): wordList = textParse(open('email/spam/%d.txt' % i).read()) docList.append(wordList) fullText.extend(wordList) classList.append(1) wordList = textParse(open('email/ham/%d.txt' % i).read()) docList.append(wordList) fullText.extend(wordList) classList.append(0) vocabList = createVocabList(docList)#create vocabulary trainingSet = range(50); testSet=[ ] #create test set for i in range(10): randIndex = int(random.uniform(0,len(trainingSet))) testSet.append(trainingSet[ randIndex ]) del(trainingSet[ randIndex ]) trainMat=[ ]; trainClasses = [ ] for docIndex in trainingSet:#train the classifier (get probs) trainNB0 trainMat.append(bagOfWords2VecMN(vocabList, docList[ docIndex ])) trainClasses.append(classList[ docIndex ]) p0V,p1V,pSpam = trainNB0(array(trainMat),array(trainClasses)) errorCount = 0 for docIndex in testSet: #classify the remaining items wordVector = bagOfWords2VecMN(vocabList, docList[ docIndex ]) if classifyNB(array(wordVector),p0V,p1V,pSpam) != classList[ docIndex ]: errorCount += 1 print ( ("classification error",docList[ docIndex ])) print ( 'the error rate is: ',float(errorCount)/len(testSet)) #return vocabList,fullText def calcMostFreq(vocabList,fullText): import operator freqDict = {} for token in vocabList: freqDict[ token ]=fullText.count(token) sortedFreq = sorted(freqDict.iteritems(), key=operator.itemgetter(1), reverse=True) return sortedFreq[ :30 ] def localWords(feed1,feed0): import feedparser docList=[ ]; classList = [ ]; fullText =[ ] minLen = min(len(feed1[ 'entries' ]),len(feed0[ 'entries' ])) for i in range(minLen): wordList = textParse(feed1[ 'entries' ][ i ][ 'summary' ]) docList.append(wordList) fullText.extend(wordList) classList.append(1) #NY is class 1 wordList = textParse(feed0[ 'entries' ][ i ][ 'summary' ]) docList.append(wordList) fullText.extend(wordList) classList.append(0) vocabList = createVocabList(docList)#create vocabulary top30Words = calcMostFreq(vocabList,fullText) #remove top 30 words for pairW in top30Words: if pairW[ 0 ] in vocabList: vocabList.remove(pairW[ 0 ]) trainingSet = range(2*minLen); testSet=[ ] #create test set for i in range(20): randIndex = int(random.uniform(0,len(trainingSet))) testSet.append(trainingSet[ randIndex ]) del(trainingSet[ randIndex ]) trainMat=[ ]; trainClasses = [ ] for docIndex in trainingSet:#train the classifier (get probs) trainNB0 trainMat.append(bagOfWords2VecMN(vocabList, docList[ docIndex ])) trainClasses.append(classList[ docIndex ]) p0V,p1V,pSpam = trainNB0(array(trainMat),array(trainClasses)) errorCount = 0 for docIndex in testSet: #classify the remaining items wordVector = bagOfWords2VecMN(vocabList, docList[ docIndex ]) if classifyNB(array(wordVector),p0V,p1V,pSpam) != classList[ docIndex ]: errorCount += 1 print ( 'the error rate is: ',float(errorCount)/len(testSet)) return vocabList,p0V,p1V def getTopWords(ny,sf): import operator vocabList,p0V,p1V=localWords(ny,sf) topNY=[ ]; topSF=[ ] for i in range(len(p0V)): if p0V[ i ] > -6.0 : topSF.append((vocabList[ i ],p0V[ i ])) if p1V[ i ] > -6.0 : topNY.append((vocabList[ i ],p1V[ i ])) sortedSF = sorted(topSF, key=lambda pair: pair[ 1 ], reverse=True) print ( "SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**") for item in sortedSF: print ( item[ 0 ]) sortedNY = sorted(topNY, key=lambda pair: pair[ 1 ], reverse=True) print ( "NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**") for item in sortedNY: print ( item[ 0 ]) 2)In order to instruction how to use methods Up, I gives an example which used to check words-list and Detail as fellowing. import bayes
ListOPosts, ListClasses = bayes.loadDataSet()
myVocabList = bayes.createVocabList(ListOPosts)
#Ok, Let's see the fianlly-result.^_^ myVocabList RUNNING RESULT AS FOLLOWING
(3)將.rar中的內容全部Copy到Python安裝目錄下的.\Lib\site-packages之下。例如: D:\Program Files\python\Lib\site-packages Until to here, we can use it. Ok, Let's see an example about Naive Bayesian Network and itsAlgorithm. 1)Naive Bayesian Network 2)Naive Bayesian Algorithm
3)I will give some net-source to you http://scikit-learn.org/stable/modules/naive_bayes.html http://www.saedsayad.com/naive_bayesian.htm http://www.saedsayad.com/naive_bayesian_exercise.htm http://www.saedsayad.com/flash/Bayesian.html Step to here, we already have prepared Programming Language, Tool of NumPy, Naive Bayesian Network and Algorithm. So, let's implement Naive Baysian Classifier by this Language & Tool &Theory.Fellow is Code-Programming, ^_^let's see it now.
''' Created on Oct 19, 2010 ''' #匯入numpy(一種開源的數值計算擴充套件,可用來儲存和處理大型矩陣) from numpy import * def loadDataSet(): postingList=[ [ 'my', 'dog', 'has', 'flea', 'problems', 'help', 'please' ], [ 'maybe', 'not', 'take', 'him', 'to', 'dog', 'park', 'stupid' ], [ 'my', 'dalmation', 'is', 'so', 'cute', 'I', 'love', 'him' ], [ 'stop', 'posting', 'stupid', 'worthless', 'garbage' ], [ 'mr', 'licks', 'ate', 'my', 'steak', 'how', 'to', 'stop', 'him' ], [ 'quit', 'buying', 'worthless', 'dog', 'food', 'stupid' ] ] classVec = [ 0,1,0,1,0,1 ] #1 is abusive, 0 not return postingList,classVec def createVocabList(dataSet): vocabSet = set([ ]) #create empty set for document in dataSet: vocabSet = vocabSet | set(document) #union of the two sets return list(vocabSet) def setOfWords2Vec(vocabList, inputSet): returnVec = [ 0 ]*len(vocabList) for word in inputSet: if word in vocabList: returnVec[ vocabList.index(word) ] = 1 else: print (("the word: %s is not in my Vocabulary!" % word)) return returnVec def trainNB0(trainMatrix,trainCategory): numTrainDocs = len(trainMatrix) numWords = len(trainMatrix[ 0 ]) pAbusive = sum(trainCategory)/float(numTrainDocs) p0Num = ones(numWords); p1Num = ones(numWords) #change to ones() p0Denom = 2.0; p1Denom = 2.0 #change to 2.0 for i in range(numTrainDocs): if trainCategory[ i ] == 1: p1Num += trainMatrix[ i ] p1Denom += sum(trainMatrix[ i ]) else: p0Num += trainMatrix[ i ] p0Denom += sum(trainMatrix[ i ]) p1Vect = log(p1Num/p1Denom) #change to log() p0Vect = log(p0Num/p0Denom) #change to log() return p0Vect,p1Vect,pAbusive def classifyNB(vec2Classify, p0Vec, p1Vec, pClass1): p1 = sum(vec2Classify * p1Vec) + log(pClass1) #element-wise mult p0 = sum(vec2Classify * p0Vec) + log(1.0 - pClass1) if p1 > p0: return 1 else: return 0 def bagOfWords2VecMN(vocabList, inputSet): returnVec = [ 0 ]*len(vocabList) for word in inputSet: if word in vocabList: returnVec[ vocabList.index(word) ] += 1 return returnVec def testingNB(): listOPosts,listClasses = loadDataSet() myVocabList = createVocabList(listOPosts) trainMat=[ ] for postinDoc in listOPosts: trainMat.append(setOfWords2Vec(myVocabList, postinDoc)) p0V,p1V,pAb = trainNB0(array(trainMat),array(listClasses)) testEntry = [ 'love', 'my', 'dalmation' ] thisDoc = array(setOfWords2Vec(myVocabList, testEntry)) print ((testEntry,'classified as: ',classifyNB(thisDoc,p0V,p1V,pAb))) testEntry = [ 'stupid', 'garbage' ] thisDoc = array(setOfWords2Vec(myVocabList, testEntry)) print ((testEntry,'classified as: ',classifyNB(thisDoc,p0V,p1V,pAb))) def textParse(bigString): #input is big string, #output is word list import re listOfTokens = re.split(r'\W*', bigString) return [ tok.lower() for tok in listOfTokens if len(tok) > 2 ] def spamTest(): docList=[ ]; classList = [ ]; fullText =[ ] for i in range(1,26): wordList = textParse(open('email/spam/%d.txt' % i).read()) docList.append(wordList) fullText.extend(wordList) classList.append(1) wordList = textParse(open('email/ham/%d.txt' % i).read()) docList.append(wordList) fullText.extend(wordList) classList.append(0) vocabList = createVocabList(docList)#create vocabulary trainingSet = range(50); testSet=[ ] #create test set for i in range(10): randIndex = int(random.uniform(0,len(trainingSet))) testSet.append(trainingSet[ randIndex ]) del(trainingSet[ randIndex ]) trainMat=[ ]; trainClasses = [ ] for docIndex in trainingSet:#train the classifier (get probs) trainNB0 trainMat.append(bagOfWords2VecMN(vocabList, docList[ docIndex ])) trainClasses.append(classList[ docIndex ]) p0V,p1V,pSpam = trainNB0(array(trainMat),array(trainClasses)) errorCount = 0 for docIndex in testSet: #classify the remaining items wordVector = bagOfWords2VecMN(vocabList, docList[ docIndex ]) if classifyNB(array(wordVector),p0V,p1V,pSpam) != classList[ docIndex ]: errorCount += 1 print ( ("classification error",docList[ docIndex ])) print ( 'the error rate is: ',float(errorCount)/len(testSet)) #return vocabList,fullText def calcMostFreq(vocabList,fullText): import operator freqDict = {} for token in vocabList: freqDict[ token ]=fullText.count(token) sortedFreq = sorted(freqDict.iteritems(), key=operator.itemgetter(1), reverse=True) return sortedFreq[ :30 ] def localWords(feed1,feed0): import feedparser docList=[ ]; classList = [ ]; fullText =[ ] minLen = min(len(feed1[ 'entries' ]),len(feed0[ 'entries' ])) for i in range(minLen): wordList = textParse(feed1[ 'entries' ][ i ][ 'summary' ]) docList.append(wordList) fullText.extend(wordList) classList.append(1) #NY is class 1 wordList = textParse(feed0[ 'entries' ][ i ][ 'summary' ]) docList.append(wordList) fullText.extend(wordList) classList.append(0) vocabList = createVocabList(docList)#create vocabulary top30Words = calcMostFreq(vocabList,fullText) #remove top 30 words for pairW in top30Words: if pairW[ 0 ] in vocabList: vocabList.remove(pairW[ 0 ]) trainingSet = range(2*minLen); testSet=[ ] #create test set for i in range(20): randIndex = int(random.uniform(0,len(trainingSet))) testSet.append(trainingSet[ randIndex ]) del(trainingSet[ randIndex ]) trainMat=[ ]; trainClasses = [ ] for docIndex in trainingSet:#train the classifier (get probs) trainNB0 trainMat.append(bagOfWords2VecMN(vocabList, docList[ docIndex ])) trainClasses.append(classList[ docIndex ]) p0V,p1V,pSpam = trainNB0(array(trainMat),array(trainClasses)) errorCount = 0 for docIndex in testSet: #classify the remaining items wordVector = bagOfWords2VecMN(vocabList, docList[ docIndex ]) if classifyNB(array(wordVector),p0V,p1V,pSpam) != classList[ docIndex ]: errorCount += 1 print ( 'the error rate is: ',float(errorCount)/len(testSet)) return vocabList,p0V,p1V def getTopWords(ny,sf): import operator vocabList,p0V,p1V=localWords(ny,sf) topNY=[ ]; topSF=[ ] for i in range(len(p0V)): if p0V[ i ] > -6.0 : topSF.append((vocabList[ i ],p0V[ i ])) if p1V[ i ] > -6.0 : topNY.append((vocabList[ i ],p1V[ i ])) sortedSF = sorted(topSF, key=lambda pair: pair[ 1 ], reverse=True) print ( "SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**SF**") for item in sortedSF: print ( item[ 0 ]) sortedNY = sorted(topNY, key=lambda pair: pair[ 1 ], reverse=True) print ( "NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**NY**") for item in sortedNY: print ( item[ 0 ]) 2)In order to instruction how to use methods Up, I gives an example which used to check words-list and Detail as fellowing. import bayes
ListOPosts, ListClasses = bayes.loadDataSet()
myVocabList = bayes.createVocabList(ListOPosts)
#Ok, Let's see the fianlly-result.^_^ myVocabList RUNNING RESULT AS FOLLOWING