• 前向最大匹配

def fmmseg(sen,max,strs):
    '''
    sen: 待切分句子
    max: 最大切分长度
    strs: 词典列表
    '''
    maxs=max
    returnlist=[]
    while len(sen)>0:
        while max>0:
            if(max==1):
                returnlist.append(sen[:1])
                sen=sen[1:]
                max=maxs
                break
            else:
                word=sen[:max]
                if(word in strs):
                    returnlist.append(word)
                    sen=sen[max:]
                    max=maxs
                    break
                else:
                    max-=1
    return returnlist

• 逆向最大匹配

def bmmseg(sen,max,strs):
    '''
    sen: 待切分句子
    max: 最大切分长度
    strs: 词典列表
    '''
    maxs=max
    returnlist=[]
    while len(sen)>0:
        while max>0:
            if(max==1):
                returnlist.append(sen[-1:])
                sen=sen[:-1]
                max=maxs
                break
            else:
                word=sen[-max:]
                if(word in strs):
                    returnlist.append(word)
                    sen=sen[:-max]
                    max=maxs
                    break
                else:
                    max-=1
    return returnlist

• 完整代码

import time
def bmmseg(sen,max,strs):
    '''
    sen: 待切分句子
    max: 最大切分长度
    strs: 词典列表
    '''
    maxs=max
    returnlist=[]
    while len(sen)>0:
        while max>0:
            if(max==1):
                returnlist.append(sen[-1:])
                sen=sen[:-1]
                max=maxs
                break
            else:
                word=sen[-max:]
                if(word in strs):
                    returnlist.append(word)
                    sen=sen[:-max]
                    max=maxs
                    break
                else:
                    max-=1
    return returnlist

def fmmseg(sen,max,strs):
    '''
    sen: 待切分句子
    max: 最大切分长度
    strs: 词典列表
    '''
    maxs=max
    returnlist=[]
    while len(sen)>0:
        while max>0:
            if(max==1):
                returnlist.append(sen[:1])
                sen=sen[1:]
                max=maxs
                break
            else:
                word=sen[:max]
                if(word in strs):
                    returnlist.append(word)
                    sen=sen[max:]
                    max=maxs
                    break
                else:
                    max-=1
    return returnlist
if __name__=="__main__":
    start=time.time()
    print("=============go=============")
    str=open("dict.txt",'r',encoding='utf-8').readlines()
    strs=[i.strip() for i in str]
    sen="你昨天晚上吃饭团了吗"
    r=fmmseg(sen,4,strs)
    print(r)
    r=bmmseg(sen,4,strs)
    print(r[::-1])
    end=time.time()
    print(end-start)

• 测试字典 dict.txt

吃饭
昨天
晚上
饭团

• 切分结果

=============go=============
['你', '昨天', '晚上', '吃饭', '团', '了', '吗']
['你', '昨天', '晚上', '吃', '饭团', '了', '吗']
0.0
[Finished in 0.2s]