python2.4升级2.7.2入门实例

对python这个高级语言感兴趣的小伙伴，下面一起跟随编程之家 jb51.cc的小编两巴掌来看看吧！

[root@~]# python

Python 2.4.3 (#1,May 5 2011,16:39:10)

[GCC 4.1.2 20080704 (Red Hat 4.1.2-50)] on linux2

Type help,copyright,credits or license for more information.

>;>>

[root@~]#

下载新版本的python

[root@~]# wget

 

解压缩 以及编译

[root@~]# tar jxvf Python-2.7.3.tar.bz2

[root@wangyuelou Python-2.7.2]# ./configure --prefix=/usr/local/python27

[root@wangyuelou Python-2.7.2]# make

[root@wangyuelou Python-2.7.2]# make install

[root@wangyuelou Python-2.7.2]# ls /usr/local/python27/ -al

total 28

drwxr-xr-x 6 root root 4096 Jul 14 00:21 .

drwxr-xr-x 20 root root 4096 Jul 14 00:17 ..

drwxr-xr-x 2 root root 4096 Jul 14 00:21 bin

drwxr-xr-x 3 root root 4096 Jul 14 00:21 include

drwxr-xr-x 4 root root 4096 Jul 14 00:21 lib

drwxr-xr-x 3 root root 4096 Jul 14 00:21 share

覆盖原来的python链接

[root@wangyuelou Python-2.7.2]# mv /usr/bin/python /usr/bin/python_old

[root@wangyuelou Python-2.7.2]# ln -s /usr/local/python27/bin/python /usr/bin/

[root@wangyuelou Python-2.7.2]# python

Python 2.7.2 (default,Jul 14 2011,00:20:14)

[GCC 4.1.2 20080704 (Red Hat 4.1.2-50)] on linux2

Type help,credits or license for more information.

>>>

此处已经可以正常使用python2.7了

但是因为yum是使用的2.4的版本来用的，所以 还需要修改一下

[root@~]# yum

There was a problem importing one of the Python modules

required to run yum. The error leading to this problem was:



No module named yum



Please install a package which provides this module,or

verify that the module is installed correctly.



It's possible that the above module doesn't match the

current version of Python,which is:

2.7.2 (default,00:20:14)

[GCC 4.1.2 20080704 (Red Hat 4.1.2-50)]



If you cannot solve this problem yourself,please go to

the yum faq at:





[root@wangyuelou Python-2.7.2]# vim /usr/bin/yum



#!/usr/bin/python #修改此处为2.4的位置

[root@~]# vim /usr/bin/yum



#!/usr/bin/python2.4

[root@~]# yum

Loaded plugins: fastestmirror

You need to give some command

usage: yum [options] COMMAND



List of Commands:



check-update Check for available package updates

clean Remove cached data

deplist List a package's dependencies

downgrade downgrade a package

erase Remove a package or packages from your system

groupinfo display details about a package group

groupinstall Install the packages in a group on your system

grouplist List available package groups

groupremove Remove the packages in a group from your system

help display a helpful usage message

info display details about a package or group of packages

install Install a package or packages on your system

list List a package or groups of packages

localinstall Install a local RPM

yum 又可以使用了)



# Process the JSON string.

results = simplejson.load(response)

# Now have some fun with the results...

实际应用中可能需要抓取google的很多网页，所以还需要使用多线程来分担抓取任务。使用google web search api的参考详细介绍，请看此处（这里介绍了Standard URL Arguments）。另外要特别注意，url中参数rsz必须是8（包括8）以下的值，若大于8，会报错的！

（3）代码实现

代码实现还存在问题，但是能够运行，鲁棒性差，还需要进行改进，希望各路大神指出错误（初学Python），不胜感激。

python代码如下：

#-*-coding:utf-8-*-
import urllib2,urllib
import simplejson
import os,time,threading
import common,html_filter
#input the keywords
keywords = raw_input('Enter the keywords: ')
#define rnum_perpage,pages
rnum_perpage=8
pages=8

#定义线程函数
def thread_scratch(url,rnum_perpage,page):
url_set = []
try:
request = urllib2.Request(url,None,{'Referer': 'http://www.sina.com'})
response = urllib2.urlopen(request)
# Process the JSON string.
results = simplejson.load(response)
info = results['responseData']['results']
except Exception,e:
print 'error occured'
print e
else:
for minfo in info:
url_set.append(minfo['url'])
print minfo['url']

#处理链接
i = 0
for u in url_set:
try:
request_url = urllib2.Request(u,{'Referer': 'http://www.sina.com'})
request_url.add_header(
'User-agent','CSC'
)
response_data = urllib2.urlopen(request_url).read()

#过滤文件
#content_data = html_filter.filter_tags(response_data)

#写入文件
filenum = i+page
filename = dir_name+'/related_html_'+str(filenum)
print ' write start: related_html_'+str(filenum)
f = open(filename,'w+',-1)
f.write(response_data)
#print content_data
f.close()
print ' write down: related_html_'+str(filenum)
except Exception,e:
print 'error occured 2'
print e
i = i+1
return

#创建文件夹
dir_name = 'related_html_'+urllib.quote(keywords)
if os.path.exists(dir_name):
print 'exists file'
common.delete_dir_or_file(dir_name)
os.makedirs(dir_name)

#抓取网页
print 'start to scratch web pages:'
for x in range(pages):
print page:%s%(x+1)
page = x * rnum_perpage
url = ('https://ajax.googleapis.com/ajax/services/search/web'
'?v=1.0&q=%s&rsz=%s&start=%s') % (urllib.quote(keywords),page)
print url
t = threading.Thread(target=thread_scratch,args=(url,page))
t.start()

#主线程等待子线程抓取完
main_thread = threading.currentThread()
for t in threading.enumerate():
if t is main_thread:
continue
t.join()
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