上一篇文章的正则，其实对很多人来说用起来是不方便的，加上需要记很多规则，所以用起来不是特别熟练，而这节我们提到的beautifulsoup就是一个非常强大的工具，爬虫利器。
beautifulSoup “美味的汤，绿色的浓汤”
一个灵活又方便的网页解析库，处理高效，支持多种解析器。
利用它就不用编写正则表达式也能方便的实现网页信息的抓取
快速使用
通过下面的一个例子，对bs4有个简单的了解，以及看一下它的强大之处：
from bs4 import BeautifulSoup
html = '''<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title"><b>The Dormouse's story</b></p>
<p class="story">Once upon a time there were three little sisters; and their names were
<a href="http://example.com/elsie" class="sister" id="link1">Elsie</a>,
<a href="http://example.com/lacie" class="sister" id="link2">Lacie</a> and
<a href="http://example.com/tillie" class="sister" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
<p class="story">...</p>'''soup = BeautifulSoup(html,'lxml')print(soup.prettify())print(soup.title)print(soup.title.name)print(soup.title.string)print(soup.title.parent.name)print(soup.p)print(soup.p["class"])print(soup.a)print(soup.find_all('a'))print(soup.find(id='link3'))