基于Markov过程的文本生成

来自复旦大学同学的python期末大作业

import re
import random
markov_dicts = {'': []}   # Start of Sentence
sentence_sep = '.?!'    # 句子结束标志
Front = re.compile(r'^[A-Z][A-Za-z]*')  # 开头的正则表达式
Middle = re.compile(r'[A-za-z]+$')   # 中间单词正则表达式
Last = re.compile(r'[A-Za-z]+[.!?]$')  # 结尾单词正则表达式


def parse(text):
    """ 分析text，产生相应的dict"""
    word_list = re.split(r'\s+', text)
    print(word_list)
    flag = 0
    for i in word_list:   # 获取开头单词
        if Front.match(i) and flag == 0:  # 如果flag等于0，且恰好处于开头单词
            markov_dicts[''].append(i)
            flag = 1
        elif Last.match(i) and flag == 1:  # 如果判断到结束的单词， 那么从新立flag=0，使下一句的开头单词正常记录
            flag = 0
    temp = word_list[0]
    word_list.pop(0)
    for i in word_list:   # 获取字典
        if temp not in markov_dicts.keys() and not Last.match(temp):  # 新建单词在字典中的键值
            markov_dicts[temp] = []
        if Last.match(temp):
            temp = i
            continue
        markov_dicts[temp].append(i)  # 记录上一个单词紧跟的单词
        temp = i


def generate(num_sentences=10, word_limit=20):
    """ 根据前面调用parse得到的dict，随机生成多个句子"""
    temp_wordnum = 1
    temp_sentencenum = 0
    temp_word = markov_dicts[''][random.randint(0, len(markov_dicts['']) - 1)]
    sentence = temp_word + ''
    while temp_sentencenum <= num_sentences:
        if Last.match(
                temp_word) or temp_wordnum > word_limit:  # 判断句子是否结束 或者 单个句子词数大于规定的数量，如果结束重新开启新的一行
            sentence += '\n'
            temp_sentencenum += 1
            temp_word = markov_dicts[''][random.randint(
                0, len(markov_dicts['']) - 1)]
            if temp_sentencenum > num_sentences:  # 判断句子数是否大于规定的数
                break
            else:
                sentence += temp_word
                temp_wordnum = 1
                continue
        temp = markov_dicts[temp_word][random.randint(
            0, len(markov_dicts[temp_word]) - 1)]  # 正常推测
        sentence += ' ' + temp
        temp_word = temp
        temp_wordnum += 1
        

    return sentence


def markov_main():
    text = 'X Y Z. X Z Y? Y X Z! Z Z Z. Y Z Y.'
#     text= '''Help, I need somebody.
# Help, not just anybody.
# Help, you know I need someone, help.
#
# When I was younger so much younger than today,
# I never needed anybody's help in any way.
# But now these days are gone, I'm not so self assured.
# Now I find I've changed my mind and opened up the doors.
#
# Help me if you can, I'm feeling down.
# And I do appreciate you being round.
# Help me get my feet back on the ground.
# Won't you please, please help me.
#
# And now my life has changed in oh so many ways.
# My independence seems to vanish in the haze.
# But every now and then I feel so insecure.
# I know that I just need you like I've never done before.
#
# Help me if you can, I'm feeling down.
# And I do appreciate you being round.
# Help me get my feet back on the ground.
# Won't you please, please help me.
#
# When I was younger so much younger than today.
# I never needed anybody's help in any way.
# But now these days are gone, I'm not so self assured.
# Now I find I've changed my mind and opened up the doors.
#
# Help me if you can, I'm feeling down.
# And I do appreciate you being round.
# Help me, get my feet back on the ground.
# Won't you please, please help me, help me, help me, ooh...
#
#
#     '''

    parse(text)
    print(generate())


if __name__ == '__main__':
    markov_main()
    generate()