Python3字节与字符串不同，startswith识别字符串方法，及pythonchallenge第四关代码

最早在做Pythonchallenge时我参考了下文的代码
https://blog.youkuaiyun.com/zrzlj/article/details/48805433
但这篇文章并不是基于Python2，有一些语法不适用

其中会发生报错

startswith first arg must be bytes or a tuple of bytes, not str

应该是说startswith只能识别bytes，不能识别str

这似乎是因为urlopen().read()，返回的是bytes类型

根据这篇文章
https://www.jianshu.com/p/efcff000b81a
Python3应该是区分了字节与字符串

所以我对代码进行了修改，下面是可以正常运行的代码

import urllib
 
def main():
    resp = urllib.request.urlopen("http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing=63579").read()
    t = 0
    while True:
        print (t)
        t = t+1
        print (resp)
        if t >= 400:
            break
        if resp.startswith(b"<font color=red>Your hands are getting tired </font>and the next nothing is "):
            resp = resp.replace(b"<font color=red>Your hands are getting tired </font>and the next nothing is ",b"")
            print(resp.decode())
            resp = urllib.request.urlopen("http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing="+resp.decode()).read()
            print(resp)
        elif resp.startswith(b"and the next nothing is "):
            resp = resp.replace(b"and the next nothing is ", b"")
            resp = urllib.request.urlopen("http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing="+resp.decode()).read()
        else:
            print (resp)
            break
 
 
 
if __name__ == '__main__':
    main()

这里对网页内容读取、判断、修改的resp变量一直为bytes型，之后因为要加入url需要转换为str型，所以参考这篇文章
https://www.cnblogs.com/niuu/p/10106897.html
我使用resp.decode进行转换