import urllib.request
import re

req=urllib.request.urlopen("http://www.imooc.com/course/list")
buf = req.read()
listurl = re.findall(r'http:.+?\.jpg',buf)

i=0
for url in listurl:
    f=open(str(i)+'.jpg','w')
    req=urllib.request.urlopen(url)
    buf= req.read()
    f.write(buf)
    i=i+1
    f.close()

错误：Traceback (most recent call last):
  File "C:\Users\zhuzhihao\Desktop\bb.py", line 6, in <module>
    listurl = re.findall(r'http:.+?\.jpg',buf)
  File "E:\python\lib\re.py", line 222, in findall
    return _compile(pattern, flags).findall(string)
TypeError: cannot use a string pattern on a bytes-like object
>>>