灵活又方便的网页解析库，处理高效，支持多种解析器。利用它不用编写正则表达式即可方便的实现网页信息的提取
安装BeautifulSoup
pip3 install beautifulsoup4
解析库
| 解析器 | 使用方法 | 优势 | 劣势 |
|---|---|---|---|
| Python标准库 | BeautifulSoup(markup,"html,parser") | Python的内置标准库，执行速度适中、文档容错能力强 | Python2.7.3 or 3.2.2前的版本中文容错能力差 |
| lxml HTML解析器 | BeautifulSoup(markup,"lxml") | 速度快、文档容错能力强 | 需要安装C语言库 |
| lxml XML解析器 | BeautifulSoup(markup,"xml") | 速度快、唯一支持XML的解析器 | 需要安装C语言库 |
| html5lib | BeautifulSoup(markup,"html5lib") | 最好的容错性、以浏览器的方式解析文档、生成HTML5格式的文档 | 速度慢、不依赖外部扩展 |
基本使用
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.prettify())
print(soup.title.string)
标签选择器
选择元素
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.title)
print(type(soup.title))
print(soup.head)
print(soup.p)
获取名称
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.title.name)
获取属性
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.p.attrs['name'])
print(soup.p['name'])
获取内容
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.p.string)
嵌套选择
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.head.title.string)
字节点和子孙节点
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.p.contents)
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.p.children)
for i,child in enumerate(soup.p.children):
print(i,child)
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.p.descendants)
for i,child in enumerate(soup.p.descendants):
print(i,child)
父节点和祖先节点
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.p.parent)
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(list(enumerate(soup.p.parent)))
兄弟节点
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(list(enumerate(soup.a.next_siblings)))
print(list(enumerate(soup.a.previous_siblings)))
标准选择器
find_all(name,attrs,recursive,text,**kwargs)
可根据标签名、属性、内容查找文档
name
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.find_all('a'))
print(type(soup.find_all('a')[0]))
html = '''
<html><head><title>The Dormouse's story</title></head>
<body>
<p class="title" name="dromouse"><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/lacle" class="sister" id="link2">Lacle</a> and
<a href="http://example.com/title" class="sister" id="link3">Title</a>;
and they lived at the bottom of a well</p>
<p class = "story">...</p>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
for p in soup.find_all('p'):
print(p.find_all('b'))
attrs
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div>
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.find_all(attrs={'id':'list-1'}))
print(soup.find_all(attrs={'name':'elements'}))
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div>
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.find_all(id='list-1'))
print(soup.find_all(class_='element'))
text
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')>
print(soup.find_all(text='Foo'))
find(name,attrs,recursive,text,**kwargs)
find返回单个元素，find_all返回所有元素
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.find('ul'))
print(type(soup.find('ul')))
print(soup.find('page'))
find_parents() find_parent()
find_parents()返回所有祖先节点，find_parent()返回直接父节点。
find_next_siblings() find_next_sibling()
find_next_siblings()返回后面所有兄弟节点，find_next_sibling()返回后面第一个兄弟节点。
find_previous_siblings() find_previous_sibling()
find_previous_siblings()返回前面所有兄弟节点，find_previous_sibling()返回前面第一个兄弟节点。
find_all_next() find_next()
find_all_next()返回节点后所有符合条件的节点，find_next()返回第一个符合条件的节点
find_all_previous()和 find_previous()
find_all_previous()返回节点前所有符合条件的节点，find_previous()返回第一个符合条件的节点
CSS选择器
通过select()直接传入CSS选择器即可完成选择
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
print(soup.select('.panel .panel-heading'))
print(soup.select('ul li'))
print(soup.select('#list-2 .element'))
print(type(soup.select('ul')[0]))
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
for ul in soup.select('ul'):
print(ul.select('li'))
获取属性
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
for ul in soup.select('ul'):
print(ul('id'))
print(ul.attrs['id'])
获取内容
html='''
<div class="panel">
<div class="panel-heading">
<h4>Hello</h4>
<div>
<div class="pannel-body">
<ul class="list" id="list-1" name="elements">
<li class="element">Foo</li>
<li class="element">Bar</li>
<li class="element">Jay</li>
</ul>
<ul class="list list-small" id="list-2">
<li class="element">Foo</li>
<li class="element">Bar</li>
</ul>
</div
<div>
'''
from bs4 import BeautifulSoup
soup = BeautifulSoup(html,'lxml')
for ul in soup.select('li'):
print(ul.get_text())
总结
- 推荐使用lxml解析库，必要时使用html.parser
- 标签选择筛选功能弱但是速度快
- 建议使用find()、find_all()查询匹配单个结果或者多个结果
- 如果对CSS选择器熟悉建议使用select