使用python获取<a>标记的内容

Question

假设我的程序中有这样的html：

<p><a href="http://vancouver.en.craigslist.ca/nvn/ret/1817849271.html">F/T &amp; P/T Sales Associate - Caliente Fashions</a> - <font size="-1"> (North Vancouver)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817804151.html">IMMEDIATE EMPLOYMENT WANTED!</a> - </p>

<p><a href="http://vancouver.en.craigslist.ca/nvn/ret/1817796152.html">TRAVEL AGENT</a> - <font size="-1"> (NORTH VANCOUVER)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/bnc/ret/1817775400.html">Optical Sales Position</a> - <font size="-1"> (New Westminster)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817709780.html">Sales Clerk</a> - <font size="-1"> (Kits)</font></p>

<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817676850.html">MARINE SALES</a> - <font size="-1"> (VANCOUVER ( KITS ))</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817608506.html">Retail Sales Associate</a> - <font size="-1"> (Vancouver)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817573985.html">Retail with small parts appliance background</a> - </p>
<p><a href="http://vancouver.en.craigslist.ca/rds/ret/1817540938.html">Manager *Enjoyable work atmosphere</a> - <font size="-1"> (Langley Centre)</font></p>

<p><a href="http://vancouver.en.craigslist.ca/bnc/ret/1817403652.html">Team Member - Retail Store - FT</a> - <font size="-1"> (Burnaby South)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/rds/ret/1817459155.html">STORE MANAGER-SHOE WAREHOUSE</a> - <font size="-1"> (South Surrey-Semiahmoo)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/pml/ret/1817448777.html">Retail Sales</a> - <font size="-1"> (Coquitlam)</font></p>

如何获取文本节点的内容？最后，我想在终端中打印与此行类似的内容：

http://vancouver.en.craigslist.ca/nvn/ret/1817849271.html - TRAVEL AGENT

到目前为止，我有下面的代码可以很好地提取ref链接，但是我不确定如何提取数据本身。我正在考虑重写sgmllib.py模块中的handle_data(self, data)，但到目前为止，我似乎还没有想出一种方法来实现它。

from sgmllib import SGMLParser

class URLLister(SGMLParser):
    def reset(self):
        SGMLParser.reset(self)
        self.urls = []

    def start_a(self, attrs):
        href = [v for k, v in attrs if k == "href"]
        if href:
            self.urls.extend(href)

谢谢！

Answer 1

SGMLParser在Python 2.6中已被弃用，并将在3.0中消失。您可能希望改用HTMLParser模块。我以前从来没有用过（我总是用小汤来做这类事情），所以我想我应该学会它的工作原理。这是我整理的一个样本脚本，可以让你得到你想要的东西。

#!/usr/bin/env python

from HTMLParser import HTMLParser

class URLParser(HTMLParser):
    def __init__(self):
        self.in_link = False
        self.links = []
        self.current_link = ''
        HTMLParser.__init__(self)

    def handle_starttag(self, tag, attrs):
        if tag == 'a':
            self.current_link = self.get_href_from_attrs(attrs)
            self.in_link = True

    def handle_endtag(self, tag):
        if tag == 'a':
            self.links.append(self.current_link)
            self.in_link = False

    def handle_data(self, data):
        if self.in_link:
            self.current_link = '%s - %s' % (self.current_link, data)

    def get_href_from_attrs(self, attrs):
        # The attrs dict is a list of tuples like:
        #  [('href', 'www.google.com'), ('class', 'some-class')]
        for prop, val in attrs:
            if prop == 'href':
                return val
        return ''

if __name__ == '__main__':
    the_html = '''
<p><a href="http://vancouver.en.craigslist.ca/nvn/ret/1817849271.html">F/T &amp; P/T Sales Associate - Caliente Fashions</a> - <font size="-1"> (North Vancouver)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817804151.html">IMMEDIATE EMPLOYMENT WANTED!</a> - </p>

<p><a href="http://vancouver.en.craigslist.ca/nvn/ret/1817796152.html">TRAVEL AGENT</a> - <font size="-1"> (NORTH VANCOUVER)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/bnc/ret/1817775400.html">Optical Sales Position</a> - <font size="-1"> (New Westminster)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817709780.html">Sales Clerk</a> - <font size="-1"> (Kits)</font></p>

<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817676850.html">MARINE SALES</a> - <font size="-1"> (VANCOUVER ( KITS ))</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817608506.html">Retail Sales Associate</a> - <font size="-1"> (Vancouver)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/van/ret/1817573985.html">Retail with small parts appliance background</a> - </p>
<p><a href="http://vancouver.en.craigslist.ca/rds/ret/1817540938.html">Manager *Enjoyable work atmosphere</a> - <font size="-1"> (Langley Centre)</font></p>

<p><a href="http://vancouver.en.craigslist.ca/bnc/ret/1817403652.html">Team Member - Retail Store - FT</a> - <font size="-1"> (Burnaby South)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/rds/ret/1817459155.html">STORE MANAGER-SHOE WAREHOUSE</a> - <font size="-1"> (South Surrey-Semiahmoo)</font></p>
<p><a href="http://vancouver.en.craigslist.ca/pml/ret/1817448777.html">Retail Sales</a> - <font size="-1"> (Coquitlam)</font></p>
    '''
    url_parser = URLParser()
    url_parser.feed(the_html)

    print '\n'.join(url_parser.links)

输出

http://vancouver.en.craigslist.ca/nvn/ret/1817849271.html - F/T  -  P/T Sales Associate - Caliente Fashions
http://vancouver.en.craigslist.ca/van/ret/1817804151.html - IMMEDIATE EMPLOYMENT WANTED!
http://vancouver.en.craigslist.ca/nvn/ret/1817796152.html - TRAVEL AGENT
http://vancouver.en.craigslist.ca/bnc/ret/1817775400.html - Optical Sales Position
http://vancouver.en.craigslist.ca/van/ret/1817709780.html - Sales Clerk
http://vancouver.en.craigslist.ca/van/ret/1817676850.html - MARINE SALES
http://vancouver.en.craigslist.ca/van/ret/1817608506.html - Retail Sales Associate
http://vancouver.en.craigslist.ca/van/ret/1817573985.html - Retail with small parts appliance background
http://vancouver.en.craigslist.ca/rds/ret/1817540938.html - Manager *Enjoyable work atmosphere
http://vancouver.en.craigslist.ca/bnc/ret/1817403652.html - Team Member - Retail Store - FT
http://vancouver.en.craigslist.ca/rds/ret/1817459155.html - STORE MANAGER-SHOE WAREHOUSE
http://vancouver.en.craigslist.ca/pml/ret/1817448777.html - Retail Sales

Update：在完成了这个小练习之后，这个界面感觉很恶心，所以我要坚持使用更干净的BeutifulSoup库。看看亚历克斯的样本，看看是怎么做的。

Answer 2

我个人会用lxml。安装后，获得所需内容非常简单：

from lxml import html

tree = html.fromstring(open("data.html").read())

print [e.text_content() for e in tree.xpath("//a")]

Answer 3

最简单的可能是BeautifulSoup（请确保使用3.0.8或更高的3.0.*版本，而不是3.1.*，除非您使用的是Python 3——请参见here！）。

import BeautifulSoup
soup = BeautifulSoup.BeautifulSoup(thehtmlstring)

for anchor in soup.findAll('a'):
  print anchor['href'], anchor.string

BeautifulSoup生成unicode字符串——如果这是个问题，请确保按照您希望的方式对它们进行编码，以获得所需的字节字符串！