Python HTML解析器BeautifulSoup用法实例详解【爬虫解析器】

本文实例讲述了Python HTML解析器BeautifulSoup用法。分享给大家供大家参考，具体如下：

BeautifulSoup简介

我们知道，Python拥有出色的内置HTML解析器模块——HTMLParser，然而还有一个功能更为强大的HTML或XML解析工具——BeautifulSoup（美味的汤），它是一个第三方库。简单来说，BeautifulSoup最主要的功能是从网页抓取数据。本文我们来感受一下BeautifulSoup的优雅而强大的功能吧！

BeautifulSoup安装

BeautifulSoup3 目前已经停止开发，推荐在现在的项目中使用BeautifulSoup4，不过它已经被移植到bs4了，也就是说导入时我们需要 import bs4 。可以利用 pip 或者 easy_install 两种方法来安装。下面采用pip安装。

pip install beautifulsoup4
pip install lxml

建议同时安装"lxml"模块，BeautifulSoup支持Python标准库中的HTML解析器（HTMLParser），还支持一些第三方的解析器，如果我们不安装它，则 Python 会使用 Python默认的解析器，lxml 解析器更加强大，速度更快，推荐安装。

创建对象

安装后，创建对象：

soup = BeautifulSoup(markup='html文件', 'lxml')

格式化输出：

soup.prettify()

BeautifulSoup四大对象类型

BeautifulSoup将复杂HTML文档转换成一个复杂的树形结构,每个节点都是Python对象,所有对象可以归纳为4种:

• Tag（标签）
• NavigableString（内容）
• BeautifulSoup（文档）
• Comment（注释）

1.Tag类型

即HTML的整个标签，如获取<title>标签：

print soup.title
#<title>The Dormouse's story</title>

Tag有两个重要属性：name，attrs。

name

即HTML的标签名称：

print soup.name
#[document]
print soup.head.name
#head

attrs

即HTML的标签属性字典：

print soup.p.attrs
#{'class': ['title'], 'name': 'dromouse'}

如果想要单独获取某个属性：

print soup.p['class']
#['title']

2.NavigableString类型

既然我们已经得到了整个标签，那么问题来了，我们要想获取标签内部的文字内容怎么办呢？很简单，用 string 即可：

print soup.p.string
#The Dormouse's story

3.BeautifulSoup类型

BeautifulSoup 对象表示的是一个文档的全部内容.：

print soup.name
# [document]

4.Comment类型

HTML的注释内容，注意的是，不包含注释符号。我们首先判断它的类型，是否为 Comment 类型，然后再进行其他操作，如打印输出：

if type(soup.a.string)==bs4.element.Comment:
  print soup.a.string
#<!-- Elsie -->

遍历文档树

1.子节点

contents

获取所有子节点，返回列表：

print soup.head.contents
#[<title>The Dormouse's story</title>]

children

获取所有子节点，返回列表生成器：

print soup.head.children
#<listiterator object at 0x7f71457f5710>
## 需要遍历
for child in soup.body.children:
  print child
## 结果
<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 class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>,
<a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a> and
<a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>;
and they lived at the bottom of a well.</p>
<p class="story">...</p>

2.节点内容

string

返回单个文本内容。如果一个标签里面没有标签了，那么 string 就会返回标签里面的内容。如果标签里面只有唯一的一个标签了，那么 string 也会返回最里面的内容。如果tag包含了多个子节点,tag就无法确定，string 方法应该调用哪个子节点的内容，string 的输出结果是 None。例如：

print soup.head.string
print soup.title.string
#The Dormouse's story
#The Dormouse's story
print soup.html.string
# None

strings

返回多个文本内容，且包含空行和空格。

stripped_strings

返回多个文本内容，且不包含空行和空格：

for string in soup.stripped_strings:
  print(repr(string))
  # u"The Dormouse's story"
  # u"The Dormouse's story"
  # u'Once upon a time there were three little sisters; and their names were'
  # u'Elsie'
  # u','
  # u'Lacie'
  # u'and'
  # u'Tillie'
  # u';\nand they lived at the bottom of a well.'
  # u'...'

get_text()方法

返回当前节点和子节点的文本内容。

from bs4 import BeautifulSoup
html_doc = """
<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" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="sister1" id="link1">Elsie</a>,
    <a href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="sister2" id="link2">Lacie</a> and
    <a href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="sister3" id="link3">Tillie</a>;
    and they lived at the bottom of a well.
  </p>
  <p class="story">...</p>
</body>
</html>
"""
soup = BeautifulSoup(markup=html_doc,features='lxml')
node_p_text=soup.find('p',class_='story').get_text()　　　　# 注意class_带下划线
print(node_p_text)
# 结果
Once upon a time there were three little sisters; and their names were
    Elsie,
    Lacie and
    Tillie;
    and they lived at the bottom of a well.

3.父节点

parent

返回某节点的直接父节点：

p = soup.p
print p.parent.name
#body

parents

返回某节点的所有父辈及以上辈的节点：

content = soup.head.title.string
for parent in content.parents:
  print parent.name
## 结果
title
head
html
[document]

4.兄弟节点

next_sibling

next_sibling 属性获取该节点的下一个兄弟节点，结果通常是字符串或空白，因为空白或者换行也可以被视作一个节点。

previous_sibling

previous_sibling 属性获取该节点的上一个兄弟节点。

print soup.p.next_sibling
#    实际该处为空白
print soup.p.prev_sibling
#None  没有前一个兄弟节点，返回 None
print soup.p.next_sibling.next_sibling
#<p class="story">Once upon a time there were three little sisters; and their names were
#<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>,
#<a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a> and
#<a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>;
#and they lived at the bottom of a well.</p>
#下一个节点的下一个兄弟节点是我们可以看到的节点

next_siblings、previous_siblings

迭代获取全部兄弟节点。

5.前后节点

next_element、previous_element

不是针对于兄弟节点，而是在于所有节点，不分层次的前一个和后一个节点。

next_elements、previous_elements

迭代获取所有前和后节点。

搜索文档树

1.find_all(name=None, attrs={}, recursive=True, text=None, limit=None, **kwargs)

find_all()方法搜索当前tag的所有tag子节点，并判断是否符合过滤器的条件。

参数说明

name参数

name参数很强大，可以传多种方式的参数，查找所有名字为 name 的tag，字符串对象会被自动忽略掉。

（a）传标签名

最简单的过滤器是标签名。在搜索方法中传入一个标签名参数，BeautifulSoup会查找与标签名完整匹配的内容，下面的例子用于查找文档中所有的<a>标签：

print soup.find_all('a')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>, <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

返回结果列表中的元素仍然是BeautifulSoup对象。

（b）传正则表达式

如果传入正则表达式作为参数，BeautifulSoup会通过正则表达式的 match() 来匹配内容。下面例子中找出所有以b开头的标签,这表示<body>和<b>标签都应该被找到：

import re
for tag in soup.find_all(re.compile("^b")):
  print(tag.name)
# body
# b

（c）传列表

如果传入列表参数，BeautifulSoup会将与列表中任一元素匹配的内容返回。下面代码找到文档中所有<a>标签和<b>标签：

soup.find_all(["a", "b"])
# [<b>The Dormouse's story</b>,
# <a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1">Elsie</a>,
# <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>,
# <a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

（d）传True

True 可以匹配任何值，下面代码查找到所有的tag，但是不会返回字符串节点：

for tag in soup.find_all(True):
  print(tag.name)
# html
# head
# title
# body
# p
# b
# p
# a
# a

（e）传函数

如果没有合适过滤器，那么还可以定义一个方法，方法只接受一个元素参数。如果这个方法返回 True 表示当前元素匹配并且被找到，如果不是则反回 False：

def has_class_but_no_id(tag):
  return tag.has_attr('class') and not tag.has_attr('id')
soup.find_all(has_class_but_no_id)
# [<p class="title"><b>The Dormouse's story</b></p>,
# <p class="story">Once upon a time there were...</p>,
# <p class="story">...</p>]

keyword参数

注意的是，如果一个指定名字的参数不是搜索内置的参数名，搜索时会把该参数当作指定名字tag的属性来搜索，如果包含一个名字为 id 的参数,BeautifulSoup会搜索每个tag的”id”属性：

soup.find_all(id='link2')
# [<a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>]

如果传入 href 参数，Beautiful Soup会搜索每个tag的"href"属性：

soup.find_all(href=re.compile("elsie"))
# [<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1">Elsie</a>]

使用多个指定名字的参数可以同时过滤tag的多个属性:

soup.find_all(href=re.compile("elsie"), id='link1')
# [<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1">three</a>]

在这里我们想用 class 过滤，不过 class 是 python 的关键词，这怎么办？加个下划线就可以：

soup.find_all("a", class_="sister")
# [<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1">Elsie</a>,
# <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>,
# <a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

attrs参数

有些tag属性在搜索不能使用,比如HTML5中的 " data-* " 自定义属性：

data_soup = BeautifulSoup('<div data-foo="value">foo!</div>')
data_soup.find_all(data-foo="value")
# SyntaxError: keyword can't be an expression
## 但是可以通过 find_all() 方法的 attrs 参数定义一个字典参数来搜索包含特殊属性的tag
data_soup.find_all(attrs={"data-foo": "value"})
# [<div data-foo="value">foo!</div>]

text参数

通过 text 参数可以搜搜文档中的字符串内容。与 name 参数的可选值一样，text 参数接受字符串 、正则表达式 、列表、True。

soup.find_all(text="Elsie")
# [u'Elsie']
soup.find_all(text=["Tillie", "Elsie", "Lacie"])
# [u'Elsie', u'Lacie', u'Tillie']
soup.find_all(text=re.compile("Dormouse"))　　# 模糊查找
[u"The Dormouse's story", u"The Dormouse's story"]

limit参数

find_all() 方法返回全部的搜索结构，如果文档树很大那么搜索会很慢。如果我们不需要全部结果，可以使用 limit 参数限制返回结果的数量。效果与SQL中的limit关键字类似，当搜索到的结果数量达到 limit 的限制时，就停止搜索返回结果。

soup.find_all("a", limit=2)
# [<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1">Elsie</a>,
# <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>]

recursive参数

调用tag的 find_all() 方法时，BeautifulSoup会检索当前tag的所有子孙节点，如果只想搜索tag的直接子节点，可以使用参数 recursive=False。

soup.html.find_all("title")
# [<title>The Dormouse's story</title>]
soup.html.find_all("title", recursive=False)
# []

2.find( name , attrs , recursive , text , **kwargs )

它与 find_all() 方法唯一的区别是 find_all() 方法的返回结果是值包含一个元素的列表，而 find() 方法直接返回结果。

3.find_parents() 和 find_parent()

find_all() 和 find() 只搜索当前节点的所有子节点，孙子节点等。find_parents() 和 find_parent() 用来搜索当前节点的父辈节点，搜索方法与普通tag的搜索方法相同，搜索文档搜索文档包含的内容。

4.find_next_siblings() 和 find_next_sibling()　　

这2个方法通过 .next_siblings 属性对当 tag 的所有后面解析的兄弟 tag 节点进行迭代， find_next_siblings() 方法返回所有符合条件的后面的兄弟节点，find_next_sibling() 只返回符合条件的后面的第一个tag节点。

5.find_previous_siblings() 和 find_previous_sibling()

这2个方法通过 .previous_siblings 属性对当前 tag 的前面解析的兄弟 tag 节点进行迭代， find_previous_siblings() 方法返回所有符合条件的前面的兄弟节点，find_previous_sibling() 方法返回第一个符合条件的前面的兄弟节点。

6.find_all_next() 和 find_next()

这2个方法通过 .next_elements 属性对当前 tag 的之后的 tag 和字符串进行迭代， find_all_next() 方法返回所有符合条件的节点， find_next() 方法返回第一个符合条件的节点。

7.find_all_previous() 和 find_previous()

这2个方法通过 .previous_elements 属性对当前节点前面的 tag 和字符串进行迭代，find_all_previous() 方法返回所有符合条件的节点， find_previous()方法返回第一个符合条件的节点。

CSS选择器

我们在写 CSS 时，标签名不加任何修饰，类名前加点，id名前加 #，在这里我们也可以利用类似的方法来筛选元素，用到的方法是 soup.select()，返回类型是 list。

通过标签名查找

print soup.select('title')
#[<title>The Dormouse's story</title>]
print soup.select('a')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>, <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]
print soup.select('b')
#[<b>The Dormouse's story</b>]

通过类名查找

print soup.select('.sister')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>, <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]

通过 id 名查找

print soup.select('#link1')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

组合查找

组合查找即和写 class 文件时，标签名与类名、id名进行的组合原理是一样的，例如查找 p 标签中，id 等于 link1的内容，二者需要用空格分开。

print soup.select('p #link1')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

直接子标签查找：

print soup.select("head > title")
#[<title>The Dormouse's story</title>]

属性查找

查找时还可以加入属性元素，属性需要用中括号括起来，注意属性和标签属于同一节点，所以中间不能加空格，否则会无法匹配到。

print soup.select('a[class="sister"]')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>, <a class="sister" href="http://example.com/lacie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link3">Tillie</a>]
print soup.select('a[href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ]')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

同样，属性仍然可以与上述查找方式组合，不在同一节点的空格隔开，同一节点的不加空格：

print soup.select('p a[href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ]')
#[<a class="sister" href="http://example.com/elsie" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" id="link1"><!-- Elsie --></a>]

以上的 select 方法返回的结果都是列表形式，可以遍历形式输出，然后用 string或get_text() 方法来获取它的内容：

soup = BeautifulSoup(html, 'lxml')
print type(soup.select('title'))
print soup.select('title')[0].get_text()
for title in soup.select('title'):
  print title.get_text()

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