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('

', 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('

', 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
换成\n

item = item.replace('\n', '').replace('
', '\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('

', 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
换成\n

item = item.replace('\n', '').replace('
', '\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。