使用Python从网页中选择特定文本

Question

Although I love the program, I've gotten extremely tired of Calibre's weekly updating habit. To counteract that problem I'm trying to work with a python script that will automate the process.

I have successfully opened the document, but I have trouble figuring out how to capture a specific piece of it for a string. Since Calibre's download link depends on the version number that needs to be retrieved. Currently line 218 contains the following:

  <a href="/projects/calibre/files/latest/download?source=files" title="/0.8.34/calibre-portable-0.8.34.zip: released on 2012-01-06 07:22:08 UTC"> 

I need to retrieve "calibre-ebook.0.8.34" from the line. Any suggestions on how to make that work?

import urllib2
print("Calibre is Updating")
url = urllib2.urlopen ( "http://sourceforge.net/projects/calibre/files" ).read()
print(url)

Answer 1

An amendment to your code:

import urllib2
import re

print("Calibre is Updating")
url = urllib2.urlopen ( "http://sourceforge.net/projects/calibre/files" ).read()

result = re.search('title="/[0-9.]*/([a-zA-Z\-]*-[0-9\.]*)', url).groups()[0][:-1]
print(result)

What I'm doing here is using the re module to search for a string that matches your request and saving it to result.

I end up stripping the last character since my regex saves an extra dot. With some patience you can really nail it down to only what you need.