今天学习了一种自然语言匹配中的中文分词方法，逆向最大匹配。
# -*- coding:utf-8 -*-
"""
author: 15025
time: 2021/8/4 7:51
software: PyCharm
Description:
逆向最大匹配: Reverse Maximum Match Method(RMM)
"""
class RMM:
def __init__(self, dict_path):
# define a dictionary set
self.dictionary = set()
# define a variable
self.maximum = 0
# read dictionary
with open(dict_path, 'r', encoding="utf-8") as f:
for line in f:
line = line.strip()
# jump the blank row in IMM_Dict file
if not line:
continue
# add reading element in our dictionary
self.dictionary.add(line)
# get the maximum length of phrase in our dictionary
if len(line) > self.maximum:
self.maximum = len(line)
# print the element in dictionary
# print(self.dictionary)
def cut(self, text):
# create a list to save the final result
result = []
index = len(text)
# if text is not bland, start matching process
while index > 0:
word = None
# start from the index of last word(self.maximum) and end at the index of first word(0)
# use the maximum matching phrase to match
for size in range(self.maximum, 0, -1):
if index - size < 0:
continue
# inverse the oder of text
# piece = text[(index - size):index]
print(piece)
if piece in self.dictionary:
word = piece
result.append(word)
index -= size
break
# if no matching is find, just decrease the index value by 1
if word is None:
index -= 1
# due to inverse matching, we need to inverse back here
return result[::-1]
if __name__ == '__main__':
text_ = "西安市大雁塔"
file_path = r"C:/Users/15025/Desktop/NLP/IMM_Dict.txt"
NLP = RMM(file_path)
print(NLP.cut(text_))
"""
['西安市', '大雁塔']
"""
其中对应的IMM_Dict字典文件内容如下图所示。
代码注释已经十分清晰了，这里不做过多的解释了，如果在阅读时遇到问题，可以评论区留言给我。
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