Python标准库04

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本文主要介绍Python标准库。

1.subprocess模块

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>>> import subprocess
>>> retcode = subprocess.call(["ls", "-l"])
#和shell中命令ls -a显示结果一样
>>> print retcode
>>> retcode = subprocess.call("ls -l",shell=True)
>>> child = subprocess.Popen(['ping','-c','4','blog.linuxeye.com'])
>>> print 'parent process'

------------------------------华丽的分割线-----------------------------

>>> import subprocess
>>> child = subprocess.Popen('ping -c4 blog.linuxeye.com',shell=True)
>>> child.wait()
>>> print 'parent process'

------------------------------华丽的分割线-----------------------------

>>> import subprocess
>>> child1 = subprocess.Popen(["ls","-l"], stdout=subprocess.PIPE)
>>> print child1.stdout.read(),
#或者child1.communicate()

------------------------------华丽的分割线-----------------------------

>>> import subprocess
>>> child1 = subprocess.Popen(["cat","/etc/passwd"], stdout=subprocess.PIPE)
>>> child2 = subprocess.Popen(["grep","0:0"],stdin=child1.stdout, stdout=subprocess.PIPE)
>>> out = child2.communicate()

2.pyinotify模块

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#!/usr/bin/python
# coding:utf-8
 
import os
from pyinotify import WatchManager, Notifier,ProcessEvent,IN_DELETE, IN_CREATE,IN_MODIFY
   
class EventHandler(ProcessEvent):
 """事件处理"""
 def process_IN_CREATE(self, event):
  print  "Create file: %s " %  os.path.join(event.path,event.name)
   
 def process_IN_DELETE(self, event):
  print  "Delete file: %s " %  os.path.join(event.path,event.name)
  
 def process_IN_MODIFY(self, event):
   print  "Modify file: %s " %  os.path.join(event.path,event.name)
   
def FSMonitor(path='.'):
  wm = WatchManager()
  mask = IN_DELETE | IN_CREATE |IN_MODIFY
  notifier = Notifier(wm, EventHandler())
  wm.add_watch(path, mask,auto_add=True,rec=True)
  print 'now starting monitor %s'%(path)
  while True:
   try:
     notifier.process_events()
     if notifier.check_events():
       notifier.read_events()
   except KeyboardInterrupt:
     notifier.stop()
     break
   
if __name__ == "__main__":
 FSMonitor('/root/softpython/apk_url')

3.pwd和grp模块

pwd模块：
pwd.getpwuid(uid):
返回对应uid的用户信息
pwd.getpwnam(name):
返回对应name的用户信息
pwd.getpwall():
返回所有用户信息
grp.getgrgid(gid):
返回对应gid的组信息
grp.getgrname(name):
返回对应group name的组信息
grp.getgrall():
返回所有组信息

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import pwd
  
def get_user():
  all_user = {}
  for user in pwd.getpwall():
    all_user[user[0]] = all_user[user[2]] = user
  return all_user
  
def userinfo(uid):
  return get_user()[uid]
  
print userinfo(0)
pwd.struct_passwd(pw_name='root', pw_passwd='x', pw_uid=0, pw_gid=0, pw_gecos='root', pw_dir='/root', pw_shell='/bin/bash')
print userinfo('root')
pwd.struct_passwd(pw_name='root', pw_passwd='x', pw_uid=0, pw_gid=0, pw_gecos='root', pw_dir='/root', pw_shell='/bin/bash')

4.pickle模块

  • 使用pickle模块将数据对象保存到文件

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    #!/usr/bin/env python
    # coding:utf-8
    import pickle

    data1 = {'a': [1, 2.0, 3, 4+6j],
             'b': ('string', u'Unicode string'),
             'c': None}

    selfref_list = [1, 2, 3]
    selfref_list.append(selfref_list)

    output = open('data.pkl', 'wb')

    #pickle.dump(obj, file, [,protocol])
    #注解：将对象obj保存到文件file中去。
    #protocol为序列化使用的协议版本
    #0：ASCII协议
    #1：老式的二进制协议
    #2：2.3版本引入的新二进制协议，较以前的更高效。
    pickle.dump(data1, output)
    pickle.dump(selfref_list, output, 2)
    output.close()

  • 使用pickle模块从文件中重构python对象

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    #!/usr/bin/env python
    # coding:utf-8

    import pprint, pickle

    pkl_file = open('data.pkl', 'rb')
    data1 = pickle.load(pkl_file)
    pprint.pprint(data1)
    data2 = pickle.load(pkl_file)
    pprint.pprint(data2)
    pkl_file.close()

5.yaml模块

  • 写入yaml文件：

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    #!/usr/bin/env python
    # coding:utf-8

    import yaml
    yaml_file = open('test.yaml','w')
    data = {'user_info':{'name':A, 'age':17}}
    yaml.dump(data,yaml_file)
    #yaml_file.truncate     //清空yaml文件
    yaml_file.close()

  • 读取yaml文件：

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    #!/usr/bin/env python
    # coding:utf-8

    import yaml
    yaml_file = open('test.yaml','r')
    yaml.load(yaml_file)
    yaml_file.close()

6.optparser模块

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#!/usr/bin/env python
# coding:utf-8

from optparse import OptionParser
usage = "myprog[ -f <filename>][-s <xyz>] arg1[,arg2..]"
optParser = OptionParser(usage)
optParser.add_option("-f","--file",action = "store",type="string",dest = "fileName")
ooptParser.add_option("-v","--vison", action="store_false", dest="verbose",default='None',
                     help="make lots of noise [default]")
fakeArgs = ['-f','file.txt','-v','good luck to you', 'arg2', 'arge']  
options, args = optParser.parse_args(fakeArgs)
print options.fileName
print options.verbose
print options
print args
print optParser.print_help()
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