爬虫的网站页面不是特别多
hash()返回的是int类型啊，有的8位，有的9位，基本上是8位。用这个来判断url重复准确吗？

多用help啊

>>> help(hash)
Help on built-in function hash in module __builtin__:

hash(...)
    hash(object) -> integer

    Return a hash value for the object.  Two objects with the same value have
    the same hash value.  The reverse is not necessarily true, but likely.