如何从python中的正则表达式匹配返回字符串? [英] How do I return a string from a regex match in python?

问题描述

我正在使用 python 脚本遍历文本文件中的行.我想在文本文档中搜索 img 标签并将标签作为文本返回.

I am running through lines in a text file using a python script. I want to search for an img tag within the text document and return the tag as text.

当我运行正则表达式 re.match(line) 时，它返回一个 _sre.SRE_MATCH 对象.我如何让它返回一个字符串?

When I run the regex re.match(line) it returns a _sre.SRE_MATCH object. How do I get it to return a string?

import sys
import string
import re

f = open("sample.txt", 'r' )
l = open('writetest.txt', 'w')

count = 1

for line in f:
    line = line.rstrip()
    imgtag  = re.match(r'<img.*?>',line)
    print("yo it's a {}".format(imgtag))

运行时打印:

yo it's a None
yo it's a None
yo it's a None
yo it's a <_sre.SRE_Match object at 0x7fd4ea90e578>
yo it's a None
yo it's a <_sre.SRE_Match object at 0x7fd4ea90e578>
yo it's a None
yo it's a <_sre.SRE_Match object at 0x7fd4ea90e578>
yo it's a <_sre.SRE_Match object at 0x7fd4ea90e5e0>
yo it's a None
yo it's a None

推荐答案

你应该使用 re.MatchObject.group(0).喜欢

imtag = re.match(r'<img.*?>', line).group(0)

你也可以做类似的事情

imgtag  = re.match(r'<img.*?>',line)
if imtag:
    print("yo it's a {}".format(imgtag.group(0)))

消除所有None.

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