案例1：利用贝叶斯方法的多项式模型分析新闻数据
数据#1
!wget http://qwone.com/~jason/20Newsgroups/20news-bydate.tar.gz
!ls
!tar -xzf 20news-bydate.tar.gz
!ls
!ls 20news-bydate-test
!ls 20news-bydate-train
!ls 20news-bydate-test/rec.autos
!cat 20news-bydate-test/rec.autos/1037
