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Python爬虫利器二之Beautiful Soup的用法

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上一节我们介绍了正则表达式，它的内容其实还是蛮多的，如果一个正则匹配稍有差池，那可能程序就处在永久的循环之中，而且有的小伙伴们也对写正则表达式的写法用得不熟练，没关系，我们还有一个更强大的工具，叫Beautiful Soup，有了它我们可以很方便地提取出HTML或XML标签中的内容，实在是方便，这一节就让我们一起来感受一下Beautiful Soup的强大吧。

1. Beautiful Soup的简介

简单来说，Beautiful Soup是python的一个库，最主要的功能是从网页抓取数据。官方解释如下：

Beautiful Soup提供一些简单的、python式的函数用来处理导航、搜索、修改分析树等功能。它是一个工具箱，通过解析文档为用户提供需要抓取的数据，因为简单，所以不需要多少代码就可以写出一个完整的应用程序。

Beautiful Soup自动将输入文档转换为Unicode编码，输出文档转换为utf-8编码。你不需要考虑编码方式，除非文档没有指定一个编码方式，这时，Beautiful Soup就不能自动识别编码方式了。然后，你仅仅需要说明一下原始编码方式就可以了。

Beautiful Soup已成为和lxml、html6lib一样出色的python解释器，为用户灵活地提供不同的解析策略或强劲的速度。

废话不多说，我们来试一下吧~

2. Beautiful Soup 安装

Beautiful Soup 3 目前已经停止开发，推荐在现在的项目中使用Beautiful Soup 4，不过它已经被移植到BS4了，也就是说导入时我们需要 import bs4 。所以这里我们用的版本是 Beautiful Soup 4.3.2 (简称BS4)，另外据说 BS4 对 Python3 的支持不够好，不过我用的是 Python2.7.7，如果有小伙伴用的是 Python3 版本，可以考虑下载 BS3 版本。

可以利用 pip 或者 easy_install 来安装，以下两种方法均可

easy_install beautifulsoup4

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easy_install beautifulsoup4

pip install beautifulsoup4

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pip install beautifulsoup4

如果想安装最新的版本，请直接下载安装包来手动安装，也是十分方便的方法。在这里我安装的是 Beautiful Soup 4.3.2

Beautiful Soup 3.2.1Beautiful Soup 4.3.2

下载完成之后解压

运行下面的命令即可完成安装

sudo python setup.py install

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sudo python setuppy install

然后需要安装 lxml

easy_install lxml

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easy_install lxml

pip install lxml

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pip install lxml

另一个可供选择的解析器是纯Python实现的 html5lib , html5lib的解析方式与浏览器相同,可以选择下列方法来安装html5lib:

easy_install html5lib

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easy_install html5lib

pip install html5lib

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pip install html5lib

Beautiful Soup支持Python标准库中的HTML解析器,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。

<thead”>

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

Python 2.7.3 or 3.2.2)前的版本中文档容错能力差

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, [“lxml”, “xml”])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

3. 开启Beautiful Soup 之旅

在这里先分享官方文档链接，不过内容是有些多，也不够条理，在此本文章做一下整理方便大家参考。

官方文档

4. 创建 Beautiful Soup 对象

首先必须要导入 bs4 库

from bs4 import BeautifulSoup

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from bs4 import BeautifulSoup

我们创建一个字符串，后面的例子我们便会用它来演示

<div id="crayon-57159b3db12af381276703" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover wrap" style=" margin-top: 12px; margin-bottom: 12px; float: left; font-size: 12px !important; line-height: 15px !important;"> <div class="crayon-toolbar" data-settings=" mouseover overlay hide delay" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;"><span class="crayon-title"></span> <div class="crayon-tools" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;"><div class="crayon-button crayon-nums-button" title="切换是否显示行编号"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-plain-button" title="纯文本显示代码"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-wrap-button" title="切换自动换行"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-expand-button" title="点击展开代码"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-copy-button" title="复制代码"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-popup-button" title="在新窗口中显示代码"><div class="crayon-button-icon"></div></div><span class="crayon-language">Python</span></div></div> <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;"></div> <div class="crayon-plain-wrap"><textarea class="crayon-plain print-no" data-settings="dblclick" readonly style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;">

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"></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> """

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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"></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>

"""

创建 beautifulsoup 对象

<div id="crayon-57159b3db12d3314882353" class="crayon-syntax crayon-theme-github crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover wrap" style=" margin-top: 12px; margin-bottom: 12px; float: left; font-size: 12px !important; line-height: 15px !important;"> <div class="crayon-toolbar" data-settings=" mouseover overlay hide delay" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;"><span class="crayon-title"></span> <div class="crayon-tools" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;"><div class="crayon-button crayon-nums-button" title="切换是否显示行编号"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-plain-button" title="纯文本显示代码"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-wrap-button" title="切换自动换行"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-expand-button" title="点击展开代码"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-copy-button" title="复制代码"><div class="crayon-button-icon"></div></div><div class="crayon-button crayon-popup-button" title="在新窗口中显示代码"><div class="crayon-button-icon"></div></div><span class="crayon-language">Python</span></div></div> <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;"></div> <div class="crayon-plain-wrap"><textarea class="crayon-plain print-no" data-settings="dblclick" readonly style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;">

soup = BeautifulSoup(html)

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soup = BeautifulSoup(html)

另外，我们还可以用本地 HTML 文件来创建对象，例如

soup = BeautifulSoup(open('index.html'))

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soup = BeautifulSoup(open('index.html'))

上面这句代码便是将本地 index.html 文件打开，用它来创建 soup 对象

下面我们来打印一下 soup 对象的内容，格式化输出

print soup.prettify()

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print soupprettify()

<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 class="sister" href="http://example.com/elsie" id="link1">  </a> , <a class="sister" href="http://example.com/lacie" id="link2"> Lacie </a> and <a class="sister" href="http://example.com/tillie" id="link3"> Tillie </a> ; and they lived at the bottom of a well. </p> <p class="story"> ... </p> </body> </html>

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<html>

<head>

<title>

The Dormouse's story

</title>

以上便是输出结果，格式化打印出了它的内容，这个函数经常用到，小伙伴们要记好咯。

5. 四大对象种类

Beautiful Soup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

NavigableString

BeautifulSoup

Comment

下面我们进行一一介绍

（1）Tag

Tag 是什么？通俗点讲就是 HTML 中的一个个标签，例如

<title>The Dormouse's story</title>

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<title>The Dormouse's story</title>

<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>

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<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>

上面的 title a 等等 HTML 标签加上里面包括的内容就是 Tag，下面我们来感受一下怎样用 Beautiful Soup 来方便地获取 Tags

下面每一段代码中注释部分即为运行结果

print soup.title

<title>The Dormouse's story</title>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db12fa576607366-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db12fa576607366-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db12fa576607366-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">title</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db12fa576607366-2"><span class="crayon-p">#<title>The Dormouse's story</title></span></div></div></td> </tr> </table> </div> </div>

print soup.head

<head><title>The Dormouse's story</title></head>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db12ff539673516-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db12ff539673516-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db12ff539673516-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db12ff539673516-2"><span class="crayon-p">#<head><title>The Dormouse's story</title></head></span></div></div></td> </tr> </table> </div> </div>

print soup.a

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1304176117448-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1304176117448-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1304176117448-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">a</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1304176117448-2"><span class="crayon-p">#<a class="sister" href="http://example.com/elsie" id="link1"></a></span></div></div></td> </tr> </table> </div> </div>

print soup.p

<p class="title" name="dromouse"><b>The Dormouse's story</b></p>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db130a682139412-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db130a682139412-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db130a682139412-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db130a682139412-2"><span class="crayon-p">#<p class="title" name="dromouse"><b>The Dormouse's story</b></p></span></div></div></td> </tr> </table> </div> </div>

我们可以利用 soup加标签名轻松地获取这些标签的内容，是不是感觉比正则表达式方便多了？不过有一点是，它查找的是在所有内容中的第一个符合要求的标签，如果要查询所有的标签，我们在后面进行介绍。

我们可以验证一下这些对象的类型

print type(soup.a)

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db130f032654774-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db130f032654774-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db130f032654774-1"><span class="crayon-e">print </span><span class="crayon-e">type</span><span class="crayon-sy">(</span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">a</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db130f032654774-2"><span class="crayon-p">#<class 'bs4.element.Tag'></span></div></div></td> </tr> </table> </div> </div>

对于 Tag，它有两个重要的属性，是 name 和 attrs，下面我们分别来感受一下

name

print soup.name print soup.head.name

[document]

head

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1315313639855-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1315313639855-2">2</div><div class="crayon-num" data-line="crayon-57159b3db1315313639855-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1315313639855-4">4</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1315313639855-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">name</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1315313639855-2"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-v">name</span></div><div class="crayon-line" id="crayon-57159b3db1315313639855-3"><span class="crayon-p">#[document]</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1315313639855-4"><span class="crayon-p">#head</span></div></div></td> </tr> </table> </div> </div>

soup 对象本身比较特殊，它的 name 即为 [document]，对于其他内部标签，输出的值便为标签本身的名称。

attrs

print soup.p.attrs

{'class': ['title'], 'name': 'dromouse'}

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db131a320246132-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db131a320246132-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db131a320246132-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-v">attrs</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db131a320246132-2"><span class="crayon-p">#{'class': ['title'], 'name': 'dromouse'}</span></div></div></td> </tr> </table> </div> </div>

在这里，我们把 p 标签的所有属性打印输出了出来，得到的类型是一个字典。

如果我们想要单独获取某个属性，可以这样，例如我们获取它的 class 叫什么

print soup.p['class']

['title']

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1320278862285-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1320278862285-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1320278862285-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">[</span><span class="crayon-s">'class'</span><span class="crayon-sy">]</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1320278862285-2"><span class="crayon-p">#['title']</span></div></div></td> </tr> </table> </div> </div>

还可以这样，利用get方法，传入属性的名称，二者是等价的

print soup.p.get('class')

['title']

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1325807929271-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1325807929271-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1325807929271-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-e">get</span><span class="crayon-sy">(</span><span class="crayon-s">'class'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1325807929271-2"><span class="crayon-p">#['title']</span></div></div></td> </tr> </table> </div> </div>

我们可以对这些属性和内容等等进行修改，例如

soup.p['class']="newClass" print soup.p

<p class="newClass" name="dromouse"><b>The Dormouse's story</b></p>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db132b246056257-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db132b246056257-2">2</div><div class="crayon-num" data-line="crayon-57159b3db132b246056257-3">3</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db132b246056257-1"><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">[</span><span class="crayon-s">'class'</span><span class="crayon-sy">]</span><span class="crayon-o">=</span><span class="crayon-s">"newClass"</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db132b246056257-2"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span></div><div class="crayon-line" id="crayon-57159b3db132b246056257-3"><span class="crayon-p">#<p class="newClass" name="dromouse"><b>The Dormouse's story</b></p></span></div></div></td> </tr> </table> </div> </div>

还可以对这个属性进行删除，例如

del soup.p['class'] print soup.p

<p name="dromouse"><b>The Dormouse's story</b></p>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1330692267560-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1330692267560-2">2</div><div class="crayon-num" data-line="crayon-57159b3db1330692267560-3">3</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1330692267560-1"><span class="crayon-e">del </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">[</span><span class="crayon-s">'class'</span><span class="crayon-sy">]</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1330692267560-2"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span></div><div class="crayon-line" id="crayon-57159b3db1330692267560-3"><span class="crayon-p">#<p name="dromouse"><b>The Dormouse's story</b></p></span></div></div></td> </tr> </table> </div> </div>

不过，对于修改删除的操作，不是我们的主要用途，在此不做详细介绍了，如果有需要，请查看前面提供的官方文档

（2）NavigableString

既然我们已经得到了标签的内容，那么问题来了，我们要想获取标签内部的文字怎么办呢？很简单，用 .string 即可，例如

print soup.p.string

The Dormouse's story

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1336953533899-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1336953533899-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1336953533899-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-t">string</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1336953533899-2"><span class="crayon-p">#The Dormouse's story</span></div></div></td> </tr> </table> </div> </div>

这样我们就轻松获取到了标签里面的内容，想想如果用正则表达式要多麻烦。它的类型是一个 NavigableString，翻译过来叫可以遍历的字符串，不过我们最好还是称它英文名字吧。

来检查一下它的类型

print type(soup.p.string)

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db133b093895693-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db133b093895693-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db133b093895693-1"><span class="crayon-e">print </span><span class="crayon-e">type</span><span class="crayon-sy">(</span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-t">string</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db133b093895693-2"><span class="crayon-p">#<class 'bs4.element.NavigableString'></span></div></div></td> </tr> </table> </div> </div>

（3）BeautifulSoup

BeautifulSoup 对象表示的是一个文档的全部内容.大部分时候,可以把它当作 Tag 对象，是一个特殊的 Tag，我们可以分别获取它的类型，名称，以及属性来感受一下

print type(soup.name)

print soup.name

[document]

print soup.attrs

{} 空字典

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1341102000835-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1341102000835-2">2</div><div class="crayon-num" data-line="crayon-57159b3db1341102000835-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1341102000835-4">4</div><div class="crayon-num" data-line="crayon-57159b3db1341102000835-5">5</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1341102000835-6">6</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1341102000835-1"><span class="crayon-e">print </span><span class="crayon-e">type</span><span class="crayon-sy">(</span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">name</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1341102000835-2"><span class="crayon-p">#<type 'unicode'></span></div><div class="crayon-line" id="crayon-57159b3db1341102000835-3"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">name</span><span class="crayon-h"> </span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1341102000835-4"><span class="crayon-p"># [document]</span></div><div class="crayon-line" id="crayon-57159b3db1341102000835-5"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">attrs</span><span class="crayon-h"> </span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1341102000835-6"><span class="crayon-p">#{} 空字典</span></div></div></td> </tr> </table> </div> </div>

（4）Comment

Comment 对象是一个特殊类型的 NavigableString 对象，其实输出的内容仍然不包括注释符号，但是如果不好好处理它，可能会对我们的文本处理造成意想不到的麻烦。

我们找一个带注释的标签

print soup.a print soup.a.string print type(soup.a.string)

1

2

3

print soupa

print soupastring

print type(soupastring)

运行结果如下

<a class="sister" href="http://example.com/elsie" id="link1"></a> Elsie <class 'bs4.element.Comment'>

1

2

3

Elsie

a 标签里的内容实际上是注释，但是如果我们利用 .string 来输出它的内容，我们发现它已经把注释符号去掉了，所以这可能会给我们带来不必要的麻烦。

另外我们打印输出下它的类型，发现它是一个 Comment 类型，所以，我们在使用前最好做一下判断，判断代码如下

if type(soup.a.string)==bs4.element.Comment: print soup.a.string

1

2

if type(soupastring)==bs4elementComment:

print soupastring

上面的代码中，我们首先判断了它的类型，是否为 Comment 类型，然后再进行其他操作，如打印输出。

6. 遍历文档树

（1）直接子节点

要点：.contents .children 属性

.contents

tag 的 .content 属性可以将tag的子节点以列表的方式输出

print soup.head.contents

[<title>The Dormouse's story</title>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1357011406515-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1357011406515-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1357011406515-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-i">contents</span> </div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1357011406515-2"><span class="crayon-p">#[<title>The Dormouse's story</title>]</span></div></div></td> </tr> </table> </div> </div>

输出方式为列表，我们可以用列表索引来获取它的某一个元素

print soup.head.contents[0]

<title>The Dormouse's story</title>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db135d181022404-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db135d181022404-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db135d181022404-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-v">contents</span><span class="crayon-sy">[</span><span class="crayon-cn">0</span><span class="crayon-sy">]</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db135d181022404-2"><span class="crayon-p">#<title>The Dormouse's story</title></span></div></div></td> </tr> </table> </div> </div>

.children

它返回的不是一个 list，不过我们可以通过遍历获取所有子节点。

我们打印输出 .children 看一下，可以发现它是一个 list 生成器对象

print soup.head.children

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1362869635809-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1362869635809-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1362869635809-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-v">children</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1362869635809-2"><span class="crayon-p">#<listiterator object at 0x7f71457f5710></span></div></div></td> </tr> </table> </div> </div>

我们怎样获得里面的内容呢？很简单，遍历一下就好了，代码及结果如下

for child in soup.body.children: print child

1

2

for child in soupbodychildren:

print child

<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" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>; and they lived at the bottom of a well.</p>

1

2

3

4

5

<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/lacie" id="link2">Lacie</a> and

（2）所有子孙节点

知识点：.descendants 属性

.descendants

.contents 和 .children 属性仅包含tag的直接子节点，.descendants 属性可以对所有tag的子孙节点进行递归循环，和 children类似，我们也需要遍历获取其中的内容。

for child in soup.descendants: print child

1

2

for child in soupdescendants:

print child

运行结果如下，可以发现，所有的节点都被打印出来了，先生最外层的 HTML标签，其次从 head 标签一个个剥离，以此类推。

<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 class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>; and they lived at the bottom of a well.</p> <p class="story">...</p> </body></html> <head><title>The Dormouse's story</title></head> <title>The Dormouse's story</title> The Dormouse's story

<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 class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>; and they lived at the bottom of a well.</p> <p class="story">...</p> </body>

<p class="title" name="dromouse"><b>The Dormouse's story</b></p> <b>The Dormouse's story</b> The Dormouse's story

<p class="story">Once upon a time there were three little sisters; and their names were <a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>; and they lived at the bottom of a well.</p> Once upon a time there were three little sisters; and their names were

<a class="sister" href="http://example.com/elsie" id="link1"></a> Elsie ,

<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> Lacie and

<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a> Tillie ; and they lived at the bottom of a well.

<p class="story">...</p> ...

1

2

3

4

5

<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

（3）节点内容

知识点：.string 属性

如果tag只有一个 NavigableString 类型子节点,那么这个tag可以使用 .string 得到子节点。如果一个tag仅有一个子节点,那么这个tag也可以使用 .string 方法,输出结果与当前唯一子节点的 .string 结果相同。

通俗点说就是：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。例如

print soup.head.string

The Dormouse's story

print soup.title.string

The Dormouse's story

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1380677265540-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1380677265540-2">2</div><div class="crayon-num" data-line="crayon-57159b3db1380677265540-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1380677265540-4">4</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1380677265540-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-t">string</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1380677265540-2"><span class="crayon-p">#The Dormouse's story</span></div><div class="crayon-line" id="crayon-57159b3db1380677265540-3"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">title</span><span class="crayon-sy">.</span><span class="crayon-t">string</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1380677265540-4"><span class="crayon-p">#The Dormouse's story</span></div></div></td> </tr> </table> </div> </div>

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

print soup.html.string

None

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1386591026964-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1386591026964-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1386591026964-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">html</span><span class="crayon-sy">.</span><span class="crayon-t">string</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1386591026964-2"><span class="crayon-p"># None</span></div></div></td> </tr> </table> </div> </div>

（4）多个内容

知识点： .strings .stripped_strings 属性

.strings

获取多个内容，不过需要遍历获取，比如下面的例子

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

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for string in soupstrings:

print(repr(string))

# u"The Dormouse's story"

# u'\n\n'

# u"The Dormouse's story"

# u'\n\n'

# u'Once upon a time there were three little sisters; and their names were\n'

# u'Elsie'

# u',\n'

# u'Lacie'

# u' and\n'

# u'Tillie'

# u';\nand they lived at the bottom of a well.'

# u'\n\n'

# u'...'

# u'\n'

.stripped_strings

输出的字符串中可能包含了很多空格或空行,使用 .stripped_strings 可以去除多余空白内容

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'...'

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for string in soupstripped_strings:

print(repr(string))

# 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'...'

（5）父节点

知识点： .parent 属性

p = soup.p print p.parent.name

body

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1396300292968-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1396300292968-2">2</div><div class="crayon-num" data-line="crayon-57159b3db1396300292968-3">3</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1396300292968-1"><span class="crayon-v">p</span><span class="crayon-h"> </span><span class="crayon-o">=</span><span class="crayon-h"> </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-i">p</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1396300292968-2"><span class="crayon-i">print</span><span class="crayon-h"> </span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-v">parent</span><span class="crayon-sy">.</span><span class="crayon-v">name</span></div><div class="crayon-line" id="crayon-57159b3db1396300292968-3"><span class="crayon-p">#body</span></div></div></td> </tr> </table> </div> </div>

content = soup.head.title.string print content.parent.name

title

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db139c448784799-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db139c448784799-2">2</div><div class="crayon-num" data-line="crayon-57159b3db139c448784799-3">3</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db139c448784799-1"><span class="crayon-v">content</span><span class="crayon-h"> </span><span class="crayon-o">=</span><span class="crayon-h"> </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-v">title</span><span class="crayon-sy">.</span><span class="crayon-t">string</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db139c448784799-2"><span class="crayon-e">print </span><span class="crayon-v">content</span><span class="crayon-sy">.</span><span class="crayon-v">parent</span><span class="crayon-sy">.</span><span class="crayon-v">name</span></div><div class="crayon-line" id="crayon-57159b3db139c448784799-3"><span class="crayon-p">#title</span></div></div></td> </tr> </table> </div> </div>

（6）全部父节点

知识点：.parents 属性

通过元素的 .parents 属性可以递归得到元素的所有父辈节点，例如

content = soup.head.title.string for parent in content.parents: print parent.name

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content = soupheadtitlestring

for parent in contentparents:

print parentname

title head html [document]

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title

head

html

[document]

（7）兄弟节点

知识点：.next_sibling .previous_sibling 属性

兄弟节点可以理解为和本节点处在统一级的节点，.next_sibling 属性获取了该节点的下一个兄弟节点，.previous_sibling 则与之相反，如果节点不存在，则返回 None

注意：实际文档中的tag的 .next_sibling 和 .previous_sibling 属性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，所以得到的结果可能是空白或者换行

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" id="link1"></a>,

<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and

<a class="sister" href="http://example.com/tillie" 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

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13ac488244566-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13ac488244566-2">2</div><div class="crayon-num" data-line="crayon-57159b3db13ac488244566-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13ac488244566-4">4</div><div class="crayon-num" data-line="crayon-57159b3db13ac488244566-5">5</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13ac488244566-6">6</div><div class="crayon-num" data-line="crayon-57159b3db13ac488244566-7">7</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13ac488244566-8">8</div><div class="crayon-num" data-line="crayon-57159b3db13ac488244566-9">9</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13ac488244566-10">10</div><div class="crayon-num" data-line="crayon-57159b3db13ac488244566-11">11</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13ac488244566-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-v">next_sibling</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13ac488244566-2"><span class="crayon-p"># 实际该处为空白</span></div><div class="crayon-line" id="crayon-57159b3db13ac488244566-3"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-v">prev_sibling</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13ac488244566-4"><span class="crayon-p">#None 没有前一个兄弟节点，返回 None</span></div><div class="crayon-line" id="crayon-57159b3db13ac488244566-5"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">p</span><span class="crayon-sy">.</span><span class="crayon-v">next_sibling</span><span class="crayon-sy">.</span><span class="crayon-v">next_sibling</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13ac488244566-6"><span class="crayon-p">#<p class="story">Once upon a time there were three little sisters; and their names were</span></div><div class="crayon-line" id="crayon-57159b3db13ac488244566-7"><span class="crayon-p">#<a class="sister" href="http://example.com/elsie" id="link1"></a>,</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13ac488244566-8"><span class="crayon-p">#<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> and</span></div><div class="crayon-line" id="crayon-57159b3db13ac488244566-9"><span class="crayon-p">#<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>;</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13ac488244566-10"><span class="crayon-p">#and they lived at the bottom of a well.</p></span></div><div class="crayon-line" id="crayon-57159b3db13ac488244566-11"><span class="crayon-p">#下一个节点的下一个兄弟节点是我们可以看到的节点</span></div></div></td> </tr> </table> </div> </div>

（8）全部兄弟节点

知识点：.next_siblings .previous_siblings 属性

通过 .next_siblings 和 .previous_siblings 属性可以对当前节点的兄弟节点迭代输出

for sibling in soup.a.next_siblings: print(repr(sibling)) # u',\n' # <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a> # u' and\n' # <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a> # u'; and they lived at the bottom of a well.' # None

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for sibling in soupanext_siblings:

print(repr(sibling))

# u',\n'

# <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>

# u' and\n'

# <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>

# u'; and they lived at the bottom of a well.'

# None

（9）前后节点

知识点：.next_element .previous_element 属性

与 .next_sibling .previous_sibling 不同，它并不是针对于兄弟节点，而是在所有节点，不分层次

比如 head 节点为

<head><title>The Dormouse's story</title></head>

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<head><title>The Dormouse's story</title></head>

那么它的下一个节点便是 title，它是不分层次关系的

print soup.head.next_element

<title>The Dormouse's story</title>

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13bd441942961-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13bd441942961-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13bd441942961-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-v">head</span><span class="crayon-sy">.</span><span class="crayon-v">next_element</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13bd441942961-2"><span class="crayon-p">#<title>The Dormouse's story</title></span></div></div></td> </tr> </table> </div> </div>

（10）所有前后节点

知识点：.next_elements .previous_elements 属性

通过 .next_elements 和 .previous_elements 的迭代器就可以向前或向后访问文档的解析内容,就好像文档正在被解析一样

for element in last_a_tag.next_elements: print(repr(element))

u'Tillie'

u';\nand they lived at the bottom of a well.'

u'\n\n'

u'...'

u'\n'

None

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13c3889385969-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13c3889385969-2">2</div><div class="crayon-num" data-line="crayon-57159b3db13c3889385969-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13c3889385969-4">4</div><div class="crayon-num" data-line="crayon-57159b3db13c3889385969-5">5</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13c3889385969-6">6</div><div class="crayon-num" data-line="crayon-57159b3db13c3889385969-7">7</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13c3889385969-8">8</div><div class="crayon-num" data-line="crayon-57159b3db13c3889385969-9">9</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13c3889385969-1"><span class="crayon-st">for</span><span class="crayon-h"> </span><span class="crayon-e">element </span><span class="crayon-st">in</span><span class="crayon-h"> </span><span class="crayon-v">last_a_tag</span><span class="crayon-sy">.</span><span class="crayon-v">next_elements</span><span class="crayon-o">:</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13c3889385969-2"><span class="crayon-h"> </span><span class="crayon-e">print</span><span class="crayon-sy">(</span><span class="crayon-e">repr</span><span class="crayon-sy">(</span><span class="crayon-v">element</span><span class="crayon-sy">)</span><span class="crayon-sy">)</span></div><div class="crayon-line" id="crayon-57159b3db13c3889385969-3"><span class="crayon-p"># u'Tillie'</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13c3889385969-4"><span class="crayon-p"># u';\nand they lived at the bottom of a well.'</span></div><div class="crayon-line" id="crayon-57159b3db13c3889385969-5"><span class="crayon-p"># u'\n\n'</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13c3889385969-6"><span class="crayon-p"># <p class="story">...</p></span></div><div class="crayon-line" id="crayon-57159b3db13c3889385969-7"><span class="crayon-p"># u'...'</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13c3889385969-8"><span class="crayon-p"># u'\n'</span></div><div class="crayon-line" id="crayon-57159b3db13c3889385969-9"><span class="crayon-p"># None</span></div></div></td> </tr> </table> </div> </div>

以上是遍历文档树的基本用法。

7.搜索文档树

（1）find_all( name , attrs , recursive , text , **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

1）name 参数

name 参数可以查找所有名字为 name 的tag,字符串对象会被自动忽略掉

A.传字符串

最简单的过滤器是字符串.在搜索方法中传入一个字符串参数,Beautiful Soup会查找与字符串完整匹配的内容,下面的例子用于查找文档中所有的<b>标签

soup.find_all('b')

[<b>The Dormouse's story</b>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13c9227962637-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13c9227962637-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13c9227962637-1"><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">find_all</span><span class="crayon-sy">(</span><span class="crayon-s">'b'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13c9227962637-2"><span class="crayon-p"># [<b>The Dormouse's story</b>]</span></div></div></td> </tr> </table> </div> </div>

print soup.find_all('a')

[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13cf384026576-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13cf384026576-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13cf384026576-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">find_all</span><span class="crayon-sy">(</span><span class="crayon-s">'a'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13cf384026576-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]</span></div></div></td> </tr> </table> </div> </div>

B.传正则表达式

如果传入正则表达式作为参数,Beautiful Soup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

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13d4802896484-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13d4802896484-2">2</div><div class="crayon-num" data-line="crayon-57159b3db13d4802896484-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13d4802896484-4">4</div><div class="crayon-num" data-line="crayon-57159b3db13d4802896484-5">5</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13d4802896484-1"><span class="crayon-e">import </span><span class="crayon-e">re</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13d4802896484-2"><span class="crayon-st">for</span><span class="crayon-h"> </span><span class="crayon-e">tag </span><span class="crayon-st">in</span><span class="crayon-h"> </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">find_all</span><span class="crayon-sy">(</span><span class="crayon-v">re</span><span class="crayon-sy">.</span><span class="crayon-e">compile</span><span class="crayon-sy">(</span><span class="crayon-s">"^b"</span><span class="crayon-sy">)</span><span class="crayon-sy">)</span><span class="crayon-o">:</span></div><div class="crayon-line" id="crayon-57159b3db13d4802896484-3"><span class="crayon-h"> </span><span class="crayon-e">print</span><span class="crayon-sy">(</span><span class="crayon-v">tag</span><span class="crayon-sy">.</span><span class="crayon-v">name</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13d4802896484-4"><span class="crayon-p"># body</span></div><div class="crayon-line" id="crayon-57159b3db13d4802896484-5"><span class="crayon-p"># b</span></div></div></td> </tr> </table> </div> </div>

C.传列表

如果传入列表参数,Beautiful Soup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" id="link1">Elsie</a>,

<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,

<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13da754075897-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13da754075897-2">2</div><div class="crayon-num" data-line="crayon-57159b3db13da754075897-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13da754075897-4">4</div><div class="crayon-num" data-line="crayon-57159b3db13da754075897-5">5</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13da754075897-1"><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">find_all</span><span class="crayon-sy">(</span><span class="crayon-sy">[</span><span class="crayon-s">"a"</span><span class="crayon-sy">,</span><span class="crayon-h"> </span><span class="crayon-s">"b"</span><span class="crayon-sy">]</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13da754075897-2"><span class="crayon-p"># [<b>The Dormouse's story</b>,</span></div><div class="crayon-line" id="crayon-57159b3db13da754075897-3"><span class="crayon-p"># <a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13da754075897-4"><span class="crayon-p"># <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,</span></div><div class="crayon-line" id="crayon-57159b3db13da754075897-5"><span class="crayon-p"># <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]</span></div></div></td> </tr> </table> </div> </div>

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

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db13df014568186-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13df014568186-2">2</div><div class="crayon-num" data-line="crayon-57159b3db13df014568186-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13df014568186-4">4</div><div class="crayon-num" data-line="crayon-57159b3db13df014568186-5">5</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13df014568186-6">6</div><div class="crayon-num" data-line="crayon-57159b3db13df014568186-7">7</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13df014568186-8">8</div><div class="crayon-num" data-line="crayon-57159b3db13df014568186-9">9</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db13df014568186-10">10</div><div class="crayon-num" data-line="crayon-57159b3db13df014568186-11">11</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db13df014568186-1"><span class="crayon-st">for</span><span class="crayon-h"> </span><span class="crayon-e">tag </span><span class="crayon-st">in</span><span class="crayon-h"> </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">find_all</span><span class="crayon-sy">(</span><span class="crayon-t">True</span><span class="crayon-sy">)</span><span class="crayon-o">:</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13df014568186-2"><span class="crayon-h"> </span><span class="crayon-e">print</span><span class="crayon-sy">(</span><span class="crayon-v">tag</span><span class="crayon-sy">.</span><span class="crayon-v">name</span><span class="crayon-sy">)</span></div><div class="crayon-line" id="crayon-57159b3db13df014568186-3"><span class="crayon-p"># html</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13df014568186-4"><span class="crayon-p"># head</span></div><div class="crayon-line" id="crayon-57159b3db13df014568186-5"><span class="crayon-p"># title</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13df014568186-6"><span class="crayon-p"># body</span></div><div class="crayon-line" id="crayon-57159b3db13df014568186-7"><span class="crayon-p"># p</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13df014568186-8"><span class="crayon-p"># b</span></div><div class="crayon-line" id="crayon-57159b3db13df014568186-9"><span class="crayon-p"># p</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db13df014568186-10"><span class="crayon-p"># a</span></div><div class="crayon-line" id="crayon-57159b3db13df014568186-11"><span class="crayon-p"># a</span></div></div></td> </tr> </table> </div> </div>

E.传方法

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 [4] ,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

下面方法校验了当前元素,如果包含 class 属性却不包含 id 属性,那么将返回 True:

def has_class_but_no_id(tag): return tag.has_attr('class') and not tag.has_attr('id')

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def has_class_but_no_id(tag):

return taghas_attr('class') and not taghas_attr('id')

将这个方法作为参数传入 find_all() 方法,将得到所有<p>标签:

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>]

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soupfind_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>]

2）keyword 参数

注意：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,Beautiful Soup会搜索每个tag的”id”属性

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

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soupfind_all(id='link2')

# [<a class="sister" href="http://example.com/lacie" 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" id="link1">Elsie</a>]

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soupfind_all(href=recompile("elsie"))

# [<a class="sister" href="http://example.com/elsie" 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" id="link1">three</a>]

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soupfind_all(href=recompile("elsie") id='link1')

# [<a class="sister" href="http://example.com/elsie" 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" id="link1">Elsie</a>,

<a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,

<a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1402413290196-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1402413290196-2">2</div><div class="crayon-num" data-line="crayon-57159b3db1402413290196-3">3</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1402413290196-4">4</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1402413290196-1"><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">find_all</span><span class="crayon-sy">(</span><span class="crayon-s">"a"</span><span class="crayon-sy">,</span><span class="crayon-h"> </span><span class="crayon-v">class_</span><span class="crayon-o">=</span><span class="crayon-s">"sister"</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1402413290196-2"><span class="crayon-p"># [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,</span></div><div class="crayon-line" id="crayon-57159b3db1402413290196-3"><span class="crayon-p"># <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>,</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1402413290196-4"><span class="crayon-p"># <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]</span></div></div></td> </tr> </table> </div> </div>

有些tag属性在搜索不能使用,比如HTML5中的 data-* 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

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data_soup = BeautifulSoup('<div data-foo="value">foo!</div>')

data_soupfind_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>]

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data_soupfind_all(attrs={"data-foo": "value"})

# [<div data-foo="value">foo!</div>]

3）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")) [u"The Dormouse's story", u"The Dormouse's story"]

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soupfind_all(text="Elsie")

# [u'Elsie']

soupfind_all(text=["Tillie" "Elsie" "Lacie"])

# [u'Elsie', u'Lacie', u'Tillie']

soupfind_all(text=recompile("Dormouse"))

[u"The Dormouse's story" u"The Dormouse's story"]

4）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.

文档树中有3个tag符合搜索条件,但结果只返回了2个,因为我们限制了返回数量

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

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soupfind_all("a" limit=2)

# [<a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>,

# <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>]

5）recursive 参数

调用tag的 find_all() 方法时,Beautiful Soup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 .

一段简单的文档:

<html> <head> <title> The Dormouse's story </title> </head> ...

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<html>

<head>

<title>

The Dormouse's story

</title>

</head>

是否使用 recursive 参数的搜索结果:

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

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souphtmlfind_all("title")

# [<title>The Dormouse's story</title>]

souphtmlfind_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() 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() 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() 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() 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

注：以上（2）（3）（4）（5）（6）（7）方法参数用法与 find_all() 完全相同，原理均类似，在此不再赘述。

8.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

（1）通过标签名查找

print soup.select('title')

[<title>The Dormouse's story</title>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db142c311375661-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db142c311375661-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db142c311375661-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'title'</span><span class="crayon-sy">)</span> </div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db142c311375661-2"><span class="crayon-p">#[<title>The Dormouse's story</title>]</span></div></div></td> </tr> </table> </div> </div>

print soup.select('a')

[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1431474758225-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1431474758225-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1431474758225-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'a'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1431474758225-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]</span></div></div></td> </tr> </table> </div> </div>

print soup.select('b')

[<b>The Dormouse's story</b>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1437188210195-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1437188210195-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1437188210195-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'b'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1437188210195-2"><span class="crayon-p">#[<b>The Dormouse's story</b>]</span></div></div></td> </tr> </table> </div> </div>

（2）通过类名查找

print soup.select('.sister')

[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db143c695098468-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db143c695098468-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db143c695098468-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'.sister'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db143c695098468-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]</span></div></div></td> </tr> </table> </div> </div>

（3）通过 id 名查找

print soup.select('#link1')

[<a class="sister" href="http://example.com/elsie" id="link1"></a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1441387495191-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1441387495191-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1441387495191-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'#link1'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1441387495191-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>]</span></div></div></td> </tr> </table> </div> </div>

（4）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" id="link1"></a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1447038060964-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1447038060964-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1447038060964-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'p #link1'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1447038060964-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>]</span></div></div></td> </tr> </table> </div> </div>

直接子标签查找

print soup.select("head > title")

[<title>The Dormouse's story</title>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db144c489744854-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db144c489744854-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db144c489744854-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">"head > title"</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db144c489744854-2"><span class="crayon-p">#[<title>The Dormouse's story</title>]</span></div></div></td> </tr> </table> </div> </div>

（5）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" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1452610856526-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1452610856526-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1452610856526-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'a[class="sister"]'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1452610856526-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>, <a class="sister" href="http://example.com/lacie" id="link2">Lacie</a>, <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>]</span></div></div></td> </tr> </table> </div> </div>

print soup.select('a[href="http://example.com/elsie"]')

[<a class="sister" href="http://example.com/elsie" id="link1"></a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db1457429908167-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db1457429908167-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db1457429908167-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'a[href="http://example.com/elsie"]'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db1457429908167-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>]</span></div></div></td> </tr> </table> </div> </div>

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"]')

[<a class="sister" href="http://example.com/elsie" id="link1"></a>]

<div class="crayon-main" style=""> <table class="crayon-table"> <tr class="crayon-row"> <td class="crayon-nums " data-settings="show"> <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;"><div class="crayon-num" data-line="crayon-57159b3db145d783708161-1">1</div><div class="crayon-num crayon-striped-num" data-line="crayon-57159b3db145d783708161-2">2</div></div> </td> <td class="crayon-code"><div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;"><div class="crayon-line" id="crayon-57159b3db145d783708161-1"><span class="crayon-e">print </span><span class="crayon-v">soup</span><span class="crayon-sy">.</span><span class="crayon-e">select</span><span class="crayon-sy">(</span><span class="crayon-s">'p a[href="http://example.com/elsie"]'</span><span class="crayon-sy">)</span></div><div class="crayon-line crayon-striped-line" id="crayon-57159b3db145d783708161-2"><span class="crayon-p">#[<a class="sister" href="http://example.com/elsie" id="link1"></a>]</span></div></div></td> </tr> </table> </div> </div>

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 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()

1

2

3

4

5

6

soup = BeautifulSoup(html 'lxml')

print type(soupselect('title'))

print soupselect('title')[0]get_text()

for title in soupselect('title'):

print titleget_text()

好，这就是另一种与 find_all 方法有异曲同工之妙的查找方法，是不是感觉很方便？

总结

本篇内容比较多，把 Beautiful Soup 的方法进行了大部分整理和总结，不过这还不算完全，仍然有 Beautiful Soup 的修改删除功能，不过这些功能用得比较少，只整理了查找提取的方法，希望对大家有帮助！小伙伴们加油！

熟练掌握了 Beautiful Soup，一定会给你带来太多方便，加油吧！

转载请注明：静觅 » Python爬虫利器二之Beautiful Soup的用法

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