刚接触到爬虫，使用 re.findall()的时候老是抛出这个错误，是正则表达式的错误么？

Question

代码如下：

import urllib.request
import re

def getHtml(url):
    page = urllib.request.urlopen(url)
    html = page.read()
    return html

def getImg(html):
    reg = r'src="(.+?\.jpg)"pic_ext'
    imgre = re.compile(reg)
    imglist = re.findall(imgre,html)
    x = 0
    for imgurl in imglist:
        urllib.urlretrieve(imgurl,'D:\E\%s.jpg' % x)
        x+=1


if __name__ == '__main__':
    html = getHtml("https://image.baidu.com/search/index?tn=baiduimage&ct=201326592&lm=-1&cl=2&ie=gb18030&word=%C3%C0%C5%AE&fr=ala&ala=1&alatpl=adress&pos=0&hs=2&xthttps=111111")
    print(getImg(html))

抛错是这样的：

   File "E:/SRCS/python/DownPic/GetPic/GetPic.py", line 12, in getImg
    imglist = re.findall(imgre,html)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python36\lib\re.py", line 222, in findall
    return _compile(pattern, flags).findall(string)
TypeError: cannot use a string pattern on a bytes-like object

Answer 1

则 re.findall 的简单用法（返回string中所有与pattern相匹配的全部字串，返回形式为数组）语法：

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        findall(pattern, string, flags=0)

    import re Python 正则表达式 re findall 方法能够以列表的形式返回能匹配的子串 # print (help(re.findall))# print (dir(re.findall)) findall查找全部r标识代表后面是正则的语句


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        regular_v1 = re.findall(r"docs","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v1)

        # ['docs']

符号^表示匹配以https开头的的字符串返回,

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        regular_v2 = re.findall(r"^https","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v2)

        # ['https']

    　　

用$符号表示以html结尾的字符串返回,判断是否字符串结束的字符串

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        regular_v3 = re.findall(r"html$","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v3)

        # ['html']

[...]匹配括号中的其中一个字符

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        regular_v4 = re.findall(r"[t,w]h","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v4)

        # ['th', 'wh']

“d”是正则语法规则用来匹配0到9之间的数返回列表

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        regular_v5 = re.findall(r"\d","https://docs.python.org/3/whatsnew/3.6.html")

        regular_v6 = re.findall(r"\d\d\d","https://docs.python.org/3/whatsnew/3.6.html/1234")

        print (regular_v5)

        # ['3', '3', '6']

        print (regular_v6)

        # ['123']

小d表示取数字0-9，大D表示不要数字，也就是出了数字以外的内容返回

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        regular_v7 = re.findall(r"\D","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v7)

        # ['h', 't', 't', 'p', 's', ':', '/', '/', 'd', 'o', 'c', 's', '.', 'p', 'y', 't', 'h', 'o', 'n', '.', 'o', 'r', 'g', '/', '/', 'w', 'h', 'a', 't', 's', 'n', 'e', 'w', '/', '.', '.', 'h', 't', 'm', 'l']

“w”在正则里面代表匹配从小写a到z,大写A到Z，数字0到9

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        regular_v8 = re.findall(r"\w","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v8)

        #['h', 't', 't', 'p', 's', 'd', 'o', 'c', 's', 'p', 'y', 't', 'h', 'o', 'n', 'o', 'r', 'g', '3', 'w', 'h', 'a', 't', 's', 'n', 'e', 'w', '3', '6', 'h', 't', 'm', 'l']

“W”在正则里面代表匹配除了字母与数字以外的特殊符号

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        regular_v9 = re.findall(r"\W","https://docs.python.org/3/whatsnew/3.6.html")

        print (regular_v9)

        # [':', '/', '/', '.', '.', '/', '/', '/', '.',

求采纳缺几个c币谢谢大佬