python url extract from html

问题:

I need python regex to extract url's from html, example html code :

<a href=""http://a0c5e.site.it/r"" target=_blank><font color=#808080>MailUp</font></a>
<a href=""http://www.site.it/prodottiLLPP.php?id=1"" class=""txtBlueGeorgia16"">Prodotti</a>
<a href=""http://www.site.it/terremoto.php"" target=""blank"" class=""txtGrigioScuroGeorgia12"">Terremoto</a>
<a class='mini' href='http://www.site.com/remove/professionisti.aspx?Id=65&Code=xhmyskwzse'>clicca qui.</a>`

I need extract only:

 http://a0c5e.site.it/r
 http://www.site.it/prodottiLLPP.php?id=1
 http://www.site.it/terremoto.php
 http://www.site.com/remove/professionisti.aspx?Id=65&Code=xhmyskwzse

回答1:

Observe

Python 2.7.3 (default, Sep  4 2012, 20:19:03) 
[GCC 4.2.1 20070831 patched [FreeBSD]] on freebsd9
Type "help", "copyright", "credits" or "license" for more information.
>>> junk=''' <a href=""http://a0c5e.site.it/r"" target=_blank><font color=#808080>MailUp</font></a>
... <a href=""http://www.site.it/prodottiLLPP.php?id=1"" class=""txtBlueGeorgia16"">Prodotti</a>
... <a href=""http://www.site.it/terremoto.php"" target=""blank"" class=""txtGrigioScuroGeorgia12"">Terremoto</a>
... <a class='mini' href='http://www.site.com/remove/professionisti.aspx?Id=65&Code=xhmyskwzse'>clicca qui.</a>`'''
>>> import re
>>> pat=re.compile(r'''http[\:/a-zA-Z0-9\.\?\=&]*''')
>>> pat.findall(junk)
['http://a0c5e.site.it/r', 'http://www.site.it/prodottiLLPP.php?id=1', 'http://www.site.it/terremoto.php', 'http://www.site.com/remove/professionisti.aspx?Id=65&Code=xhmyskwzse']

Might want to add % so you can catch other escapes.

回答2:

Regex might solve your problem, but consider using BeautifulSoup

>>> html = """<a href="http://a0c5e.site.it/r" target=_blank><font color=#808080>MailUp</font></a>
<a href="http://www.site.it/prodottiLLPP.php?id=1" class=""txtBlueGeorgia16"">Prodotti</a>
<a href="http://www.site.it/terremoto.php" target=""blank"" class=""txtGrigioScuroGeorgia12"">Terremoto</a>
<a class='mini' href='http://www.site.com/remove/professionisti.aspx?Id=65&Code=xhmyskwzse'>clicca qui.</a>`"""
>>> from BeautifulSoup import BeautifulSoup
>>> soup = BeautifulSoup(html)
>>> [e['href'] for e in soup.findAll('a')]
[u'http://a0c5e.site.it/r', u'http://www.site.it/prodottiLLPP.php?id=1', u'http://www.site.it/terremoto.php', u'http://www.site.com/remove/professionisti.aspx?Id=65&Code=xhmyskwzse']

From Jon Clements

soup.findAll('a', {'href': True}) 

On a different note, your href quotaion in your html snippet is incorrect.

回答3:

You can use BeautifulSoup library to manipulate/extract information on HTML.

I don't recommend you to use regular expressions to parse HTML data. HTML is not regular, it's context-free grammar. When a link structure changes, HTML can be valid but your regex may not , and you will have to write the expression again. Using BeautifulSoup is a decent way to extract information.