概述
1. 简介
Beautiful Soup 是一个可以从HTML或XML文件中提取数据的Python库.
安装方法:
pip install beautifulsoup4
网页解析器
由于Beautiful Soup是对HTML文件进行提取数据，因此，需要安装网页解析器。
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,其中一个是 lxml .根据操作系统不同,可以选择下列方法来安装lxml: $ 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:$ pip install html5lib
几种网页解析器对比
推荐使用lxml作为解析器,因为效率更高.
2. 方法
使用BeautifulSoup解析这段代码,能够得到一个 BeautifulSoup 的对象,并能按照标准的缩进格式的结构输出:
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_doc)
print(soup.prettify())
效果：
# <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="link2">
# Tillie
# </a>
# ; and they lived at the bottom of a well.
# </p>
# <p class="story">
# ...
# </p>
# </body>
# </html>
几个简单的浏览结构化数据的方法:
soup.title
# <title>The Dormouse's story</title>
soup.title.name
# u'title'
soup.title.string
# u'The Dormouse's story'
soup.title.parent.name
# u'head'
soup.p
# <p class="title"><b>The Dormouse's story</b></p>
soup.p['class']
# u'title'
soup.a
# <a class="sister" href="http://example.com/elsie" id="link1">Elsie</a>
soup.find_all('a')
# [<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>]
soup.find(id="link3")
# <a class="sister" href="http://example.com/tillie" id="link3">Tillie</a>
从文档中找到所有<a>标签的链接:
for link in soup.find_all('a'):
print(link.get('href'))
# http://example.com/elsie
# http://example.com/lacie
# http://example.com/tillie
从文档中获取所有文字内容:
print(soup.get_text())
# 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.
#
# ...
3. 简单的应用
爬取的网站：howbuy.com, 爬取基金的代码，名称等
from selenium import webdriver
from bs4 import BeautifulSoup
import time
driver = webdriver.Chrome(executable_path="E:Google Chromechromedriver_win32chromedriver.exe") #用chrome浏览器打开
url = "https://www.howbuy.com/fund/fundranking/"
driver.get(url)
time.sleep(2) #让操作稍微停一下
cookie=driver.get_cookies()
time.sleep(3)
# 网页内容
html = driver.page_source
soup1 = BeautifulSoup(html,'lxml')
for info in soup1.find_all('tr'):
td = info.find_all('td')
link = td.find('a').get('href')
name = td.find('a').contents[0]
print("基金名称：{}，基金的详细链接：{}".format(name, link))
网页中是：
<tr><td class="ck" width="4%"><input onclick="move(this);" type="checkbox" value="007350"/></td><td width="4%">1</td><td width="6%"><a href="https://www.howbuy.com/fund/007350" target="_blank">007350</a></td><td class="tdl" width="13%"><a href="https://www.howbuy.com/fund/007350" target="_blank">华夏科技创新混合C</a></td><td width="5%">01-26</td><td class="tdr" width="6%">2.5793</td><td class="tdr" width="7%"><span class="cRed">3.02%</span></td><td class="tdr" width="7%"><span class="cRed">13.21%</span></td><td class="tdr" width="7%"><span class="cRed">157.93%</span></td><td class="tdr" width="7%"><span class="cRed">157.93%</span></td><td class="tdr" width="7%"><span class="cRed">157.93%</span></td><td class="tdr" width="8%"><span class="cRed">7.49%</span></td><td class="tdr" width="10%"><span class="cRed">13.21%</span></td><td class="handle" width="9%"><a href="https://trade.ehowbuy.com/newpc/pcfund/module/pcfund/view/buyFund.html?fundCode=007350" target="_blank">购买</a><a class="add_select addzx_007350" href="javascript:void(0)" jjdm-data="007350" onclick='MoveBox(this,"007350")' target="_self">自选</a><a class="c666 delzx_007350" href="javascript:void(0)" onclick='delFund("007350")' style="display: none; color: rgb(102, 102, 102);" target="_self">已自选</a></td></tr>
效果：
基金名称：浦银安盛环保新能源混合A，基金的详细链接：https://www.howbuy.com/fund/007163
参考：
- Beautiful Soup 4.2.0 文档;
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