爬虫之BeautifulSoup类

佚名 4年前 (2020-03-15) Python 569人围观抢沙发百度已收录

安装：pip install BeautifulSoup4

下表列出了主要的解析器,以及它们的优缺点:看个人习惯选取自己喜欢的解析方式

SRE实战互联网时代守护先锋，助力企业售后服务体系运筹帷幄！一键直达领取阿里云限量特价优惠。

 1 # 获取html代码
 2 import requests  3 r = requests.get('http://www.python123.io/ws/demo.html')  4 demo = r.text  5 from bs4 import BeautifulSoup  6 soup = BeautifulSoup(demo,'html.parser')  7 print(soup.prettify()) #按照标准的缩进格式的结构输出，代码如下
 8 <html>
 9  <head>
10   <title>
11    This is a python demo page 12   </title>
13  </head>
14  <body>
15   <p class="title">
16    <b>
17  The demo python introduces several python courses. 18    </b>
19   </p>
20   <p class="course">
21    Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses: 22    <a class="py1" href="http://www.icourse163.org/course/BIT-268001" id="link1">
23  Basic Python 24    </a>
25    and
26    <a class="py2" href="http://www.icourse163.org/course/BIT-1001870001" id="link2">
27  Advanced Python 28    </a>
29  . 30   </p>
31  </body>
32 </html>

简单浏览数据化方法的用法

#demo的源代码
html_d=""" <html><head><title>This is a python demo page</title></head> <body> <p class="title"><b>The demo python introduces several python courses.</b></p> <p class="course">Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses: <a href="http://www.icourse163.org/course/BIT-268001" class="py1" id="link1">Basic Python</a> and <a href="http://www.icourse163.org/course/BIT-1001870001" class="py2" id="link2">Advanced Python</a>.</p> </body></html> """
from bs4 import BeautifulSoup soup=BeautifulSoup(html_d,'html.parser') # 获取title标签
print(soup.title) #获取文本内容
print(soup.text) #获取标签名称
print(soup.title.name) #获取标签属性
print(soup.title.attrs) #获取head标签的子节点
print(soup.p.contents) print(soup.p.children) #获取所有的a标签
print(soup.find_all('a'))

常用解析方法

#demo的源代码
html_d=""" <html><head><title>This is a python demo page</title></head> <body> <p class="title"><b>The demo python introduces several python courses.</b></p> <p class="course">Python is a wonderful general-purpose programming language. You can learn Python from novice to professional by tracking the following courses: <a href="http://www.icourse163.org/course/BIT-268001" class="py1" id="link1">Basic Python</a> and <a href="http://www.icourse163.org/course/BIT-1001870001" class="py2" id="link2">Advanced Python</a>.</p> </body></html> """
from bs4 import BeautifulSoup soup = BeautifulSoup(html_d,"lxml") #p下面所有的子节点
print(soup.p.contents) soup.contents[0].name #children本身没有子节点，得到一个迭代器,包含p下所有子节点
print(soup.p.children) for child in enumerate(soup.p.children): print(child) #子孙节点p下面所有的标签都会出来
print(soup.p.descendants) for i in enumerate(soup.p.children): print(i) # string 下面有且只有一个子节皆可以取出，如有多个字节则返回为none
print(soup.title.string) # strings 如果有多个字符串
for string in soup.strings: print(repr(string)) #去掉空白
for line in soup.stripped_strings: print(line) #获取a标签的父节点
print(soup.a.parent) #找到a标签的父辈节点
print(soup.a.parents) #兄弟节点
print(soup.a.next_sibling) #同一个兄弟
print(soup.a.next_sibling) #上一个兄弟
print(soup.a.next_sibling) #下一个兄弟

find_all的用法( name, attrs, recursive, text, **kwargs)

import re
from bs4 import BeautifulSoup
soup = BeautifulSoup(html_d,"lxml")
# name
for tag in soup.find_all(re.compile('b')):
print(tag.name)
#attrs
print(soup.find_all('p','course'))
#keyword
print(soup.find_all(id='link1'))
#recursive
# print(soup.find_all('a',recursive=False))
# string
# print(soup.find_all(string=re.compile('python')))

小案例

import requests from bs4 import BeautifulSoup import bs4 #获取URL里面信息
def getHtmlText(url): try: r= requests.get(url,timeout=30 ) r.encoding=r.apparent_encoding return r.text except: return ""
#提起网页数据
def fillunivList(ulist,html): soup = BeautifulSoup(html,"html.parser") for tr in soup.find('tbody').children: if isinstance(tr,bs4.element.Tag): tds = tr('td') ulist.append([tds[0].string,tds[1].string,tds[2].string,tds[3].string]) pass
#打印数据结果
def printUnivList(ulist,num): # tplt = "{0:^10}\t{1:{3}^10}\t{2:^10}\t{:^10}"
    # print(tplt.format('排名', '学校名称', '省份','总分',chr(12288)))
    # for i in range(num):
    # u = ulist[i]
    # print(tplt.format(u[0], u[1], u[2],u[3],chr(12288)))
    print("{:^10}\t{:^6}\t{:^10}\t{:^10}".format('排名', '学校名称', '地区', '总分')) for i in range(num): u = ulist[i] print("{:^10}\t{:^6}\t{:^10}\t{:^10}".format(u[0], u[1], u[2], u[3])) return
def main(): unifo = [] url = 'http://www.zuihaodaxue.cn/zuihaodaxuepaiming2019.html' html = getHtmlText(url) fillunivList(unifo,html) printUnivList(unifo,20) #打印前20所
main()