python 中文分词——FMM 算法

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,知道句子结束。

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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')

测试代码:

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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")

文本测试代码:

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test = open("test.txt","r")
for line in test:
s = FMM(CovertGBKtoUTF(line),dictions)
for i in s:
print i.decode("utf-8")

  • 本文作者: 帐前卒
  • 本文链接: http://chillyc.info/2009/4291222/
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