使用方法：把训练文本放在目录test\test.txt里，然后运行程序

import random


def flist(item="", lst=None):
    tmp = []
    tag = 0
    for i in lst:
        if i == item:
            tmp.append(tag)
        tag += 1
    return tmp


inp = input("初始文本：")
word = int(input("单词数："))

with open("test/test.txt", "r") as file:
    a = "".join(file.readlines(50000)).split(" ") + [" "]
    for i in range(word):
        if inp.split(" ")[-1] in a:
            inp = inp + " " + a[random.choice(flist(inp.split(" ")[-1], a)) + 1]
        else:
            inp = inp + ", end."
            break
print(inp)