【python】python2.x 与 python3.x区别对照+缩进错误解决方法

仅仅列出我用到的，不全。

划重点：

　　1. urllib2 用 urllib.request 代替

　　2. urllib.urlencode 用 urllib.parse.urlencode 代替

　　3. cookielib 用 http.cookiejar 代替

　　4. print " " 用 print(" ") 代替

　　5. urllib2.URLError 用 urllib.error.URLError 代替

　　6. urllib2.HTTPError 用 urllib.error.HTTPError 代替

　　7. except urllib2.URLError, e: 用 except urllib.error.URLError as e: 代替

在python3.4.3自带的IDLE中写代码，经常出现缩进错误，很难查找。

解决方案：拷贝到Notepad++里面，视图中显示空格和制表符，就可以明显看出问题在哪了。

设置了header的网络请求，在Python2.x中的写法

import urllib

import urllib2  

url = 'http://www.server.com/login'

user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'

values = {'username' : 'kzy',  'password' : '' }

headers = { 'User-Agent' : user_agent }

data = urllib.urlencode(values)

request = urllib2.Request(url, data, headers)

response = urllib2.urlopen(request)

page = response.read()

在Python3.x中的写法

import urllib.parse

import urllib.request

url = 'http://www.baidu.com'

user_agent = 'Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.93 Safari/537.36'

values = {'username':'kzy','password':''}

headers = {'User-Agent':user_agent}

data = urllib.parse.urlencode(values).encode(encoding='UTF8') #这里要指明编码方式

request = urllib.request.Request(url, data, headers)

response = urllib.request.urlopen(request)

page = response.read()

我在学习静觅的爬虫教程，照着把里面的基础部分的代码都写了一遍。

教程地址：http://cuiqingcai.com/1052.html

里面原本的代码都是2.x的，我全部用3.x学着写了一遍。如下：

import urllib.parse

import urllib.request

"""

response = urllib.request.urlopen("http://www.baidu.com")

print(response.read())

"""

"""

#设置了header和data的请求

url = 'http://www.baidu.com'

user_agent = 'Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.93 Safari/537.36'

values = {'username':'kzy','password':'123'}

headers = {'User-Agent':user_agent}

data = urllib.parse.urlencode(values).encode(encoding='UTF8')

request = urllib.request.Request(url, data, headers)

response = urllib.request.urlopen(request)

page = response.read()

"""

"""

#设置代理  避免因为某个IP的访问次数过多导致的禁止访问

enable_proxy = True

proxy_handler = urllib.request.ProxyHandler({"http":'http://some-proxy.com:8080'})

null_proxy_handler = urllib.request.ProxyHandler({})

if enable_proxy:

    opener = urllib.request.build_opener(proxy_handler)

else:

    opener = urllib.request.build_opener(null_proxy_handler)

urllib.request.install_opener(opener)    

"""

"""

#设置Timeout

response = urllib.request.urlopen('http://www.baidu.com', timeout = 10)

"""

"""

#使用http的 put或delete方法

url = 'http://www.baidu.com'

request = urllib.request.Request(url, data=data)

request.get_method = lambda:'PUT' #or 'DELETE'

response = urllib.request.urlopen(request)

"""

"""

#使用DebugLog 把收发包的内容在屏幕上打印出来 方便调试

httpHandler = urllib.request.HTTPHandler(debuglevel=1)

httpsHandler = urllib.request.HTTPSHandler(debuglevel=1)

opener = urllib.request.build_opener(httpHandler, httpsHandler)

urllib.request.install_opener(opener)

response = urllib.request.urlopen('https://its.pku.edu.cn/netportal/netportal_UTF-8.jsp', timeout = 5)

"""

"""

#URLError异常处理

from urllib.error import URLError, HTTPError

request = urllib.request.Request('http://www.baidu.com')

try:

    urllib.request.urlopen(request, timeout = 5)

except HTTPError as e:

    print('Error code:', e.code)

except URLError as e:

       print('Reason:', e.reason)

"""

"""

#URLError异常处理 属性判断

request = urllib.request.Request('https://its.pku.edu.cn/netportal/netportal_UTF-8.jsp')

try:

    urllib.request.urlopen(request, timeout = 5)

except urllib.error.URLError as e:

    if hasattr(e, "code"):     #hasattr 判断变量是否有某个属性

        print(e.code)

    if hasattr(e, "reason"):

        print(e.reason)

else:

    print("OK")

"""

"""

#获取cookie保存到变量

import http.cookiejar

#声明一个CookieJar对象实例来保存cookie

cookie = http.cookiejar.CookieJar()

#利用HTTPCookieProcessor对象来创建cookie处理器

handler = urllib.request.HTTPCookieProcessor(cookie)

#通过handler来构建opener

opener = urllib.request.build_opener(handler)

#此处的open方法同urlopen

response = opener.open('https://its.pku.edu.cn/netportal/netportal_UTF-8.jsp')

for item in cookie:

    print('Name = '+item.name)

    print('Value = '+item.value)

"""

"""

#获取cookie保存到文件

import http.cookiejar

#设置保存的文件

filename = 'cookie.txt'

#声明一个MozillaCookieJar对象实例来保存cookie，之后写入文件

cookie = http.cookiejar.MozillaCookieJar(filename)

#创建cookie处理器

handler = urllib.request.HTTPCookieProcessor(cookie)

#构建opener

opener = urllib.request.build_opener(handler)

response = opener.open("https://its.pku.edu.cn/netportal/netportal_UTF-8.jsp")

#保存到cookie文件

cookie.save(ignore_discard=True,ignore_expires=True)

"""

"""

#从文件中获取cookie并访问

import http.cookiejar

#创建MozillaCookieJar实例对象

cookie = http.cookiejar.MozillaCookieJar()

#从文件中读取cookie内容到变量

cookie.load('cookie.txt',ignore_discard=True,ignore_expires=True)

#创建请求的request

req = urllib.request.Request('https://its.pku.edu.cn/netportal/netportal_UTF-8.jsp')

#创建opener

opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cookie))

response = opener.open(req)

print(response.read())

"""

#模拟登陆 登陆不成功

import http.cookiejar

filename = 'cookie.txt'

cookie = http.cookiejar.MozillaCookieJar(filename)

opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cookie))

postdata = urllib.parse.urlencode({'stuid':'******','pwd':'******'}).encode(encoding='UTF8') #这里怎么知道名字分别是stuid和pwd呢？？？

loginUrl = 'http://xxxxxx.com'

result = opener.open(loginUrl, postdata)

cookie.save(ignore_discard=True, ignore_expires=True)

gradeUrl='http://xxxxxx.com'

result = opener.open(gradeUrl)

print(result.read())

巴特西

【python】python2.x 与 python3.x区别对照+缩进错误解决方法

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