Python爬虫包BeautifulSoup实例（三）

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。

python 爬虫包 BeautifulSoup