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
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# -*- 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。
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# -*- 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
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# -*- 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
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# -*- 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
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# -*- 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)
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# -*- 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服务器之家。
原文链接:https://blog.csdn.net/u013007900/article/details/53820825