机器学习12—FP-growth学习笔记
test12.py
#-*- coding:utf-8 import sys sys.path.append("fpGrowth.py") import fpGrowth from numpy import * # rootNode = fpGrowth.treeNode('pyramid', 9, None) # rootNode.children['eye'] = fpGrowth.treeNode('eye', 13, None) # rootNode.children['phoenix'] = fpGrowth.treeNode('phoenix', 3, None) # rootNode.disp() simpDat = fpGrowth.loadSimpDat() # print(simpDat) initSet = fpGrowth.createInitSet(simpDat) # print(initSet) myFPtree, myHeaderTab = fpGrowth.createTree(initSet, 3) # myFPtree.disp() # resX = fpGrowth.findPrefixPath('x', myHeaderTab['x'][1]) # print(resX) # resZ = fpGrowth.findPrefixPath('z', myHeaderTab['z'][1]) # print(resZ) # resR = fpGrowth.findPrefixPath('r', myHeaderTab['r'][1]) # print(resR) freqItems = [] fpGrowth.mineTree(myFPtree, myHeaderTab, 3, set([]), freqItems) print("freqItems:") print(freqItems) print("over!!!")
fpGrowth.py
''' Created on Jun 14, 2011 FP-Growth FP means frequent pattern the FP-Growth algorithm needs: 1. FP-tree (class treeNode) 2. header table (use dict) This finds frequent itemsets similar to apriori but does not find association rules. @author: Peter ''' class treeNode: def __init__(self, nameValue, numOccur, parentNode): self.name = nameValue self.count = numOccur self.nodeLink = None self.parent = parentNode #needs to be updated self.children = {} def inc(self, numOccur): self.count += numOccur def disp(self, ind=1): print(' '*ind, self.name, ' ', self.count) for child in self.children.values(): child.disp(ind+1) def createTree(dataSet, minSup=1): #create FP-tree from dataset but don't mine headerTable = {} #go over dataSet twice for trans in dataSet:#first pass counts frequency of occurance for item in trans: # test0 = headerTable.get(item, 0) # test1 = dataSet[trans] headerTable[item] = headerTable.get(item, 0) + dataSet[trans] for k in list(headerTable): #remove items not meeting minSup if headerTable[k] < minSup: del(headerTable[k]) freqItemSet = set(headerTable.keys()) #print 'freqItemSet: ',freqItemSet if len(freqItemSet) == 0: return None, None #if no items meet min support -->get out for k in headerTable: headerTable[k] = [headerTable[k], None] #reformat headerTable to use Node link #print('headerTable: ',headerTable) retTree = treeNode('Null Set', 1, None) #create tree for tranSet, count in dataSet.items(): #go through dataset 2nd time localD = {} for item in tranSet: #put transaction items in order if item in freqItemSet: localD[item] = headerTable[item][0] if len(localD) > 0: orderedItems = [v[0] for v in sorted(localD.items(), key=lambda p: p[1], reverse=True)] updateTree(orderedItems, retTree, headerTable, count)#populate tree with ordered freq itemset return retTree, headerTable #return tree and header table def updateTree(items, inTree, headerTable, count): if items[0] in inTree.children:#check if orderedItems[0] in retTree.children inTree.children[items[0]].inc(count) #incrament count else: #add items[0] to inTree.children inTree.children[items[0]] = treeNode(items[0], count, inTree) if headerTable[items[0]][1] == None: #update header table headerTable[items[0]][1] = inTree.children[items[0]] else: updateHeader(headerTable[items[0]][1], inTree.children[items[0]]) if len(items) > 1:#call updateTree() with remaining ordered items updateTree(items[1::], inTree.children[items[0]], headerTable, count) def updateHeader(nodeToTest, targetNode): #this version does not use recursion while (nodeToTest.nodeLink != None): #Do not use recursion to traverse a linked list! nodeToTest = nodeToTest.nodeLink nodeToTest.nodeLink = targetNode def ascendTree(leafNode, prefixPath): #ascends from leaf node to root if leafNode.parent != None: prefixPath.append(leafNode.name) ascendTree(leafNode.parent, prefixPath) def findPrefixPath(basePat, treeNode): #treeNode comes from header table condPats = {} while treeNode != None: prefixPath = [] ascendTree(treeNode, prefixPath) if len(prefixPath) > 1: condPats[frozenset(prefixPath[1:])] = treeNode.count treeNode = treeNode.nodeLink return condPats def mineTree(inTree, headerTable, minSup, preFix, freqItemList): bigL = [v[0] for v in sorted(headerTable.items(), key=lambda p: p[1][0])]#(sort header table) for basePat in bigL: #start from bottom of header table newFreqSet = preFix.copy() newFreqSet.add(basePat) #print('finalFrequent Item: ',newFreqSet) #append to set freqItemList.append(newFreqSet) condPattBases = findPrefixPath(basePat, headerTable[basePat][1]) #print('condPattBases :',basePat, condPattBases) #2. construct cond FP-tree from cond. pattern base myCondTree, myHead = createTree(condPattBases, minSup) #print('head from conditional tree: ', myHead) if myHead != None: #3. mine cond. FP-tree print('conditional tree for: ',newFreqSet) myCondTree.disp(1) mineTree(myCondTree, myHead, minSup, newFreqSet, freqItemList) def loadSimpDat(): simpDat = [['r', 'z', 'h', 'j', 'p'], ['z', 'y', 'x', 'w', 'v', 'u', 't', 's'], ['z'], ['r', 'x', 'n', 'o', 's'], ['y', 'r', 'x', 'z', 'q', 't', 'p'], ['y', 'z', 'x', 'e', 'q', 's', 't', 'm']] return simpDat def createInitSet(dataSet): retDict = {} for trans in dataSet: retDict[frozenset(trans)] = 1 return retDict import twitter from time import sleep import re def textParse(bigString): urlsRemoved = re.sub('(http:[/][/]|www.)([a-z]|[A-Z]|[0-9]|[/.]|[~])*', '', bigString) listOfTokens = re.split(r'\W*', urlsRemoved) return [tok.lower() for tok in listOfTokens if len(tok) > 2] def getLotsOfTweets(searchStr): CONSUMER_KEY = '' CONSUMER_SECRET = '' ACCESS_TOKEN_KEY = '' ACCESS_TOKEN_SECRET = '' api = twitter.Api(consumer_key=CONSUMER_KEY, consumer_secret=CONSUMER_SECRET, access_token_key=ACCESS_TOKEN_KEY, access_token_secret=ACCESS_TOKEN_SECRET) #you can get 1500 results 15 pages * 100 per page resultsPages = [] for i in range(1,15): print("fetching page %d" % i) searchResults = api.GetSearch(searchStr, per_page=100, page=i) resultsPages.append(searchResults) sleep(6) return resultsPages def mineTweets(tweetArr, minSup=5): parsedList = [] for i in range(14): for j in range(100): parsedList.append(textParse(tweetArr[i][j].text)) initSet = createInitSet(parsedList) myFPtree, myHeaderTab = createTree(initSet, minSup) myFreqList = [] mineTree(myFPtree, myHeaderTab, minSup, set([]), myFreqList) return myFreqList #minSup = 3 #simpDat = loadSimpDat() #initSet = createInitSet(simpDat) #myFPtree, myHeaderTab = createTree(initSet, minSup) #myFPtree.disp() #myFreqList = [] #mineTree(myFPtree, myHeaderTab, minSup, set([]), myFreqList)