python实现中文分词FMM算法实例

本文实例讲述了python/' target='_blank'>python实现中文分词FMM算法。分享给大家供大家参考。具体分析如下：

FMM算法的最简单思想是使用贪心算法向前找n个，如果这n个组成的词在词典中出现，就ok，如果没有出现，那么找n-1个...然后继续下去。假如n个词在词典中出现，那么从n+1位置继续找下去，直到句子结束。

import re  def PreProcess(sentence,edcode="utf-8"):    sentence = sentence.decode(edcode)    sentence=re.sub(u"[。，,！……!《》<>\"':：？\?、\|“”‘'；]"," ",sentence)    return sentence  def FMM(sentence,diction,result = [],maxwordLength = 4,edcode="utf-8"):  i = 0   sentence = PreProcess(sentence,edcode)    length = len(sentence)    while i < length:     # find the ascii word      tempi=i      tok=sentence[i:i+1]      while re.search("[0-9A-Za-z\-\+#@_\.]{1}",tok)<>None:        i= i+1       tok=sentence[i:i+1]      if i-tempi>0:        result.append(sentence[tempi:i].lower().encode(edcode))     # find chinese word      left = len(sentence[i:])      if left == 1:        """go to 4 step over the FMM"""       """should we add the last one? Yes, if not blank"""       if sentence[i:] <> " ":          result.append(sentence[i:].encode(edcode))        return result      m = min(left,maxwordLength)      for j in xrange(m,0,-1):        leftword = sentence[i:j+i].encode(edcode)      #  print leftword.decode(edcode)        if LookUp(leftword,diction):         # find the left word in dictionary         # it's the right one          i = j+i          result.append(leftword)          break       elif j == 1:          """only one word, add into result, if not blank"""         if leftword.decode(edcode) <> " ":            result.append(leftword)          i = i+1       else:          continue   return result  def LookUp(word,dictionary):    if dictionary.has_key(word):      return True   return False def ConvertGBKtoUTF(sentence):    return sentence.decode('gbk').encode('utf-8')dictions = {}  dictions["ab"] = 1 dictions["cd"] = 2 dictions["abc"] = 1 dictions["ss"] = 1 dictions[ConvertGBKtoUTF("好的")] = 1 dictions[ConvertGBKtoUTF("真的")] = 1 sentence = "asdfa好的是这样吗vasdiw呀真的daf dasfiw asid是吗？" s = FMM(ConvertGBKtoUTF(sentence),dictions)  for i in s:    print i.decode("utf-8")test = open("test.txt","r")  for line in test:    s = FMM(CovertGBKtoUTF(line),dictions)    for i in s:      print i.decode("utf-8")

运行结果如下：

asdfa
好的
是
这
样
吗
vasdiw
呀
真的
daf
dasfiw
asid
是
吗
？

希望本文所述对大家的Python程序设计有所帮助。