python BeautifulSoup4

source form http://www.bkjia.com/ASPjc/908009.html

昨天把传说中的BeautifulSoup4装上了，还没有装好的童鞋，请看本人的上一篇博客：

Python3 Win7安装 BeautifulSoup，按照里面简单的步骤就可以把BeautifulSoup装上啦，很简单的，表害怕

装好BeautifulSoup4之后，就让我们来好好享受这碗BeautifulSoup吧，哈哈

入门：

下面就来介绍一下BeautifulSoup吧，BeautifulSoup是一个可以从HTML或XML文件中提取数据的 Python库.它能够通过你喜欢的转换器实现惯用的文档导航,查找,修改文档的方式.Beautiful Soup会帮你节省数小时甚至数天的工作时间

在你知道有BeautifulSoup这货之前，如果你从一个文本中提取出自己想要的东西，那么估计你应该使用re模块，但先在如果给你一个HTML文件让你提取出一些关键信息，如果再使用re模块，虽然也可以把信息提取出来，但是捏，你可能会绞尽脑汁苦思冥想查阅好多资料，现在，我们有了BeautifulSoup，一切变得超级简单起来，对，就是这么简单

实践：

学习bs4最好的还是查看bs4的官方文档，有中文版的哦，猛点这里官方文档，看起来会很快，笔者花了大概一个下午的时间，把bs4的官方文档看了一遍，顺手也写了写里面的示例程序，如果你没多少时间的话，看看我下面的代码，估计你会很快上手的，相信我 (*^_^*)

__author__ = 'MrChen'

from bs4 import BeautifulSoup

#这是示例

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" class="sister" id="link1">Elsie</a>,

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

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

and they lived at the bottom of a well.</p>

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

"""

#初始化，实例化一个BeautifulSoup对象，参数可以是一个字符串，也可以是一个打开的文件比如open('mydoc.html')

soup = BeautifulSoup(html_doc)

print(soup.title)

#输出：<title>The Dormouse's story</title>

print(soup.title.parent)

#输出：<head><title>The Dormouse's story</title></head>

print(soup.title.parent.parent)

#输出：

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

print(soup.title.name)

#输出：title

print(soup.title.parent.name)

#输出：head

print(soup.title.parent.parent.name)

#输出：html

print(soup.p)

#输出：<p class="title"><b>The Dormouse's story</b></p>

print(soup.p['class'])

#输出：['title']

print(soup.a)

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

print(soup.find_all('a'))

#输出：

#[<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>]

print(soup.find(id = 'link3'))

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

for link in soup.find_all('a'):

    print(link.get('href'))

#输出：

# http://example.com/elsie

# http://example.com/lacie

# http://example.com/tillie

print(soup.getText())

#输出：

# The Dormouse's story

#

# The Dormouse's story

# 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.

# ...

print('all tags : <<<<<<')

for tag in soup.find_all(True):

    print(tag.name)

#输出：

#html

#head

#title

#body

#p

#b

#p

#a

#a

#a

#p

怎使用python+beautifulsoup获取img中alt的中文信息

你好：
请看下面代码：
from bs4 import
BeautifulSouphtml="你的地址"soup=
BeautifulSoup(html)trs=soup.findAll("img")length=len(trs)for i in
range(length): print trs[i].attrs["alt"]记得采纳哦！

python使用BeautifulSoup解析html出现的问题

用这两个参数：findAll('div',{'class':'content'})