python实现中文分词FMM算法实例

本文实例讲述了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。