Python爬虫包BeautifulSoup实例（三）

更新时间：2020-06-06 15:00:01 作者：startmvc

一步一步构建一个爬虫实例，抓取糗事百科的段子先不用beautifulsoup包来进行解析第一步，

一步一步构建一个爬虫实例，抓取糗事百科的段子

先不用beautifulsoup包来进行解析

第一步，访问网址并抓取源码


# -*- coding: utf-8 -*-
# @Author: HaonanWu
# @Date: 2016-12-22 16:16:08
# @Last Modified by: HaonanWu
# @Last Modified time: 2016-12-22 20:17:13

import urllib
import urllib2
import re
import os

if __name__ == '__main__':
 # 访问网址并抓取源码
 url = 'http://www.qiushibaike.com/textnew/page/1/?s=4941357'
 user_agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36'
 headers = {'User-Agent':user_agent}
 try:
 request = urllib2.Request(url = url, headers = headers)
 response = urllib2.urlopen(request)
 content = response.read()
 except urllib2.HTTPError as e:
 print e
 exit()
 except urllib2.URLError as e:
 print e
 exit()
 print content.decode('utf-8')

第二步，利用正则表达式提取信息

首先先观察源码中，你需要的内容的位置以及如何识别然后用正则表达式去识别读取注意正则表达式中的 . 是不能匹配\n的，所以需要设置一下匹配模式。


# -*- coding: utf-8 -*-
# @Author: HaonanWu
# @Date: 2016-12-22 16:16:08
# @Last Modified by: HaonanWu
# @Last Modified time: 2016-12-22 20:17:13

import urllib
import urllib2
import re
import os

if __name__ == '__main__':
 # 访问网址并抓取源码
 url = 'http://www.qiushibaike.com/textnew/page/1/?s=4941357'
 user_agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36'
 headers = {'User-Agent':user_agent}
 try:
 request = urllib2.Request(url = url, headers = headers)
 response = urllib2.urlopen(request)
 content = response.read()
 except urllib2.HTTPError as e:
 print e
 exit()
 except urllib2.URLError as e:
 print e
 exit()

 regex = re.compile('<div class="content">.*?<span>(.*?)</span>.*?</div>', re.S)
 items = re.findall(regex, content)

 # 提取数据
 # 注意换行符，设置 . 能够匹配换行符
 for item in items:
 print item

第三步，修正数据并保存到文件中


# -*- coding: utf-8 -*-
# @Author: HaonanWu
# @Date: 2016-12-22 16:16:08
# @Last Modified by: HaonanWu
# @Last Modified time: 2016-12-22 21:41:32

import urllib
import urllib2
import re
import os

if __name__ == '__main__':
 # 访问网址并抓取源码
 url = 'http://www.qiushibaike.com/textnew/page/1/?s=4941357'
 user_agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36'
 headers = {'User-Agent':user_agent}
 try:
 request = urllib2.Request(url = url, headers = headers)
 response = urllib2.urlopen(request)
 content = response.read()
 except urllib2.HTTPError as e:
 print e
 exit()
 except urllib2.URLError as e:
 print e
 exit()

 regex = re.compile('<div class="content">.*?<span>(.*?)</span>.*?</div>', re.S)
 items = re.findall(regex, content)

 # 提取数据
 # 注意换行符，设置 . 能够匹配换行符
 path = './qiubai'
 if not os.path.exists(path):
 os.makedirs(path)
 count = 1
 for item in items:
 #整理数据，去掉\n,将<br/>换成\n
 item = item.replace('\n', '').replace('<br/>', '\n')
 filepath = path + '/' + str(count) + '.txt'
 f = open(filepath, 'w')
 f.write(item)
 f.close()
 count += 1

第四步，将多个页面下的内容都抓取下来


# -*- coding: utf-8 -*-
# @Author: HaonanWu
# @Date: 2016-12-22 16:16:08
# @Last Modified by: HaonanWu
# @Last Modified time: 2016-12-22 20:17:13

import urllib
import urllib2
import re
import os

if __name__ == '__main__':
 # 访问网址并抓取源码
 path = './qiubai'
 if not os.path.exists(path):
 os.makedirs(path)
 user_agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36'
 headers = {'User-Agent':user_agent}
 regex = re.compile('<div class="content">.*?<span>(.*?)</span>.*?</div>', re.S)
 count = 1
 for cnt in range(1, 35):
 print '第' + str(cnt) + '轮'
 url = 'http://www.qiushibaike.com/textnew/page/' + str(cnt) + '/?s=4941357'
 try:
 request = urllib2.Request(url = url, headers = headers)
 response = urllib2.urlopen(request)
 content = response.read()
 except urllib2.HTTPError as e:
 print e
 exit()
 except urllib2.URLError as e:
 print e
 exit()
 # print content

 # 提取数据
 # 注意换行符，设置 . 能够匹配换行符
 items = re.findall(regex, content)

 # 保存信息
 for item in items:
 # print item
 #整理数据，去掉\n,将<br/>换成\n
 item = item.replace('\n', '').replace('<br/>', '\n')
 filepath = path + '/' + str(count) + '.txt'
 f = open(filepath, 'w')
 f.write(item)
 f.close()
 count += 1

 print '完成'

使用BeautifulSoup对源码进行解析


# -*- coding: utf-8 -*-
# @Author: HaonanWu
# @Date: 2016-12-22 16:16:08
# @Last Modified by: HaonanWu
# @Last Modified time: 2016-12-22 21:34:02

import urllib
import urllib2
import re
import os
from bs4 import BeautifulSoup

if __name__ == '__main__':
 url = 'http://www.qiushibaike.com/textnew/page/1/?s=4941357'
 user_agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36'
 headers = {'User-Agent':user_agent}
 request = urllib2.Request(url = url, headers = headers)
 response = urllib2.urlopen(request)
 # print response.read()
 soup_packetpage = BeautifulSoup(response, 'lxml')
 items = soup_packetpage.find_all("div", class_="content")

 for item in items:
 try:
 content = item.span.string
 except AttributeError as e:
 print e
 exit()

 if content:
 print content + "\n"

这是用BeautifulSoup去抓取书本以及其价格的代码可以通过对比得出到bs4对标签的读取以及标签内容的读取（因为我自己也没有学到这一部分，目前只能依葫芦画瓢地写）


# -*- coding: utf-8 -*-
# @Author: HaonanWu
# @Date: 2016-12-22 20:37:38
# @Last Modified by: HaonanWu
# @Last Modified time: 2016-12-22 21:27:30
import urllib2
import urllib
import re 

from bs4 import BeautifulSoup 


url = "https://www.packtpub.com/all"
try:
 html = urllib2.urlopen(url) 
except urllib2.HTTPError as e:
 print e
 exit()

soup_packtpage = BeautifulSoup(html, 'lxml') 
all_book_title = soup_packtpage.find_all("div", class_="book-block-title") 

price_regexp = re.compile(u"\s+\$\s\d+\.\d+") 

for book_title in all_book_title: 
 try:
 print "Book's name is " + book_title.string.strip()
 except AttributeError as e:
 print e
 exit()
 book_price = book_title.find_next(text=price_regexp) 
 try:
 print "Book's price is "+ book_price.strip()
 except AttributeError as e:
 print e
 exit()
 print ""

以上全部为本篇文章的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。