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Python爬虫——抓取贴吧帖子
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抓取百度贴吧帖子
按照这个学习教程，一步一步写出来，中间遇到很多的问题，一一列举
首先， 获得 标题 和 贴子总数
# -*- coding:utf-8 -*-
#!/user/bin/python import urllib
import urllib2
import re class BDTB:
#初始化，传入基地址，是否只看楼主的参数
def __init__(self, baseUrl, seeLZ):
self.baseURL = baseUrl
self.seeLZ = '?see_lz=' + str(seeLZ) #传入页码，获取该页帖子的代码
def getPage(self, pageNum):
try:
url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)
request = urllib2.Request(url)
response = urllib2.urlopen(request)
return response.read()
except urllib2.URLError, e:
if hasattr(e, "reason"):
print u"连接百度贴吧失败,错误原因", e.reason
return None def getTitle(self):
page = self.getPage(1)
pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>', re.S)
result = re.search(pattern, page)
if result:
print result.group(1)
return result.group(1).strip()
else:
return None #得到帖子页数
def getPageNum(self):
page = self.getPage(1)
pattern = re.compile('<li class="l_reply_num.*?<span.*?>(.*?)</span',re.S)
result = re.search(pattern, page)
if result:
print "回复个数："
print result.group(1)
return result.group(1).strip()
else:
return None baseURL = 'http://tieba.baidu.com/p/3138733512'
bdtb = BDTB(baseURL, 1)
bdtb.getTitle()
bdtb.getPageNum()
PS：我用的火狐浏览器，查看网页源代码，鼠标右击查看 获得 快捷键 Ctrl-U
接下来 抓取 楼层的内容，写好的 程序如下
import urllib
import urllib2
import re class BDTB:
#初始化，传入基地址，是否只看楼主的参数
def __init__(self, baseUrl, seeLZ):
self.baseURL = baseUrl
self.seeLZ = '?see_lz=' + str(seeLZ) #传入页码，获取该页帖子的代码
def getPage(self, pageNum):
try:
url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)
request = urllib2.Request(url)
response = urllib2.urlopen(request)
return response.read()
except urllib2.URLError, e:
if hasattr(e, "reason"):
print u"连接百度贴吧失败,错误原因", e.reason
return None def getTitle(self):
page = self.getPage(1)
pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>', re.S)
result = re.search(pattern, page)
if result:
print result.group(1)
return result.group(1).strip()
else:
return None #得到帖子页数
def getPageNum(self):
page = self.getPage(1)
pattern = re.compile('<li class="l_reply_num.*?<span.*?>(.*?)</span',re.S)
result = re.search(pattern, page)
if result:
print "回复个数："
print result.group(1)
return result.group(1).strip()
else:
return None def getContent(self,page):
pattern = re.compile('<div id="post_content_.*? class="d_post_content j_d_post_content ">(.*?)</div>',re.S)
items = re.findall(pattern,page)
for item in items:
print item baseURL = 'http://tieba.baidu.com/p/3138733512'
bdtb = BDTB(baseURL, 1)
bdtb.getTitle()
bdtb.getPageNum()
bdtb.getContent(1)
但是运行之后一直报错，如下图：
检查代码无数次后，终于.....发现 getContent中 没有获取页码 T_T 在这个函数首句加上
page = self.getPage(1)
即可！！！
终于得到了内容部分，用一下工具类 可将乱七八糟的图片什么的代码去掉
#处理页面标签类
class Tool:
#去除img标签,7位长空格
removeImg = re.compile('<img.*?>| {7}|')
#删除超链接标签
removeAddr = re.compile('<a.*?>|</a>')
#把换行的标签换为\n
replaceLine = re.compile('<tr>|<div>|</div>|</p>')
#将表格制表<td>替换为\t
replaceTD= re.compile('<td>')
#把段落开头换为\n加空两格
replacePara = re.compile('<p.*?>')
#将换行符或双换行符替换为\n
replaceBR = re.compile('<br><br>|<br>')
#将其余标签剔除
removeExtraTag = re.compile('<.*?>')
def replace(self,x):
x = re.sub(self.removeImg,"",x)
x = re.sub(self.removeAddr,"",x)
x = re.sub(self.replaceLine,"\n",x)
x = re.sub(self.replaceTD,"\t",x)
x = re.sub(self.replacePara,"\n ",x)
x = re.sub(self.replaceBR,"\n",x)
x = re.sub(self.removeExtraTag,"",x)
#strip()将前后多余内容删除
return x.strip()
最后最后，就是这样的了..
# -*- coding:utf-8 -*-
#!/user/bin/python import urllib
import urllib2
import re #处理页面标签类
class Tool:
#去除img标签,7位长空格
removeImg = re.compile('<img.*?>| {7}|')
#删除超链接标签
removeAddr = re.compile('<a.*?>|</a>')
#把换行的标签换为\n
replaceLine = re.compile('<tr>|<div>|</div>|</p>')
#将表格制表<td>替换为\t
replaceTD= re.compile('<td>')
#把段落开头换为\n加空两格
replacePara = re.compile('<p.*?>')
#将换行符或双换行符替换为\n
replaceBR = re.compile('<br><br>|<br>')
#将其余标签剔除
removeExtraTag = re.compile('<.*?>')
def replace(self,x):
x = re.sub(self.removeImg,"",x)
x = re.sub(self.removeAddr,"",x)
x = re.sub(self.replaceLine,"\n",x)
x = re.sub(self.replaceTD,"\t",x)
x = re.sub(self.replacePara,"\n ",x)
x = re.sub(self.replaceBR,"\n",x)
x = re.sub(self.removeExtraTag,"",x)
#strip()将前后多余内容删除
return x.strip() class BDTB:
#初始化，传入基地址，是否只看楼主的参数
def __init__(self, baseUrl, seeLZ, floorTag):
self.baseURL = baseUrl
self.seeLZ = '?see_lz=' + str(seeLZ)
self.tool = Tool()
#全局file变量，文件写入操作对象
self.file = None
#楼层标号， 初始化为1
self.floor = 1
#默认标题
self.defaultTitle = u"百度某某贴吧"
#是否写入楼层分隔符标记
self.floorTag = floorTag #传入页码，获取该页帖子的代码
def getPage(self, pageNum):
try:
url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)
request = urllib2.Request(url)
response = urllib2.urlopen(request)
return response.read().decode('utf-8')
except urllib2.URLError, e:
if hasattr(e, "reason"):
print u"连接百度贴吧失败,错误原因", e.reason
return None #获得帖子标题
def getTitle(self,page):
page = self.getPage(1)
pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>', re.S)
result = re.search(pattern, page)
if result:
#print result.group(1)
return result.group(1).strip()
else:
return None #得到帖子页数
def getPageNum(self,page):
page = self.getPage(1)
pattern = re.compile('<li class="l_reply_num.*?<span.*?>(.*?)</span',re.S)
result = re.search(pattern, page)
if result:
#print "回复个数："
#print result.group(1)
return result.group(1).strip()
else:
return None #获得帖子的内容
def getContent(self,page):
page = self.getPage(1)
pattern = re.compile('<div id="post_content_.*?>(.*?)</div>',re.S)
items = re.findall(pattern,page)
contents = []
floor = 1
for item in items:
content = "\n" + self.tool.replace(item) + "\n"
contents.append(content.encode('utf-8'))
#print self.tool.replace(item)
#floor += 1
return contents def setFileTitle(self,title):
if title is not None:
self.file = open(title + ".txt", "w+")
else:
self.file = open(self.defaultTitle + ".txt", "w+") def writeData(self,contents):
for item in contents:
if self.floorTag == '':
floorline = "\n" + str(self.floor) + u"-------------------------------------\n"
self.file.write(floorline)
self.file.write(item)
self.floor += 1 def start(self):
indexPage = self.getPage(1)
pageNum = self.getPageNum(indexPage)
title = self.getTitle(indexPage)
self.setFileTitle(title)
if pageNum == None:
print "URL已失效，请重试"
return
try:
print "该帖子共有" + str(pageNum) + "页"
for i in range(1,int(pageNum) + 1):
print "正在写入第" + str(i) + "页数据"
page = self.getPage(i)
contents = self.getContent(page)
self.writeData(contents)
except IOError,e:
print "写入异常，原因" + e.message
finally:
print "Succeed~" print u"请输入帖子代码"
baseURL = 'http://tieba.baidu.com/p/' + str(raw_input(u'http://tieba.baidu.com/p/'))
seeLZ = raw_input("是否只看楼主，是输入1，否输入0\\n")
floorTag = raw_input("是否写入楼层信息，是输入1，否输入0\\n")
bdtb = BDTB(baseURL, seeLZ,floorTag)
bdtb.start()
关于decode和encode知识，查看 这个
关于raw_input, 查看 这个
