产生所需要的正弦信号，并把信号保存到本地，实现信号的存储-Sinusoidal signal need, and save the signal to local signals for storage

使用爬虫从豆瓣官网获得影评TOP250的电影，以Excel文件的形式存储在本地。(Use the crawler to get the top 250 movie reviews from Douban official website and store them locally as Excel files.)