import os.path
for path in [ '/one/two/three',
        '/one/two/three/',
        '/',
        '.',
        '']:
  print 's : %s' % (path, os.path.split(path))

 /one/two/three : ('/one/two', 'three')
/one/two/three/ : ('/one/two/three', '')
       / : ('/', '')
       . : ('', '.')
        : ('', '')

import os.path
for path in [ '/one/two/three',
        '/one/two/three/',
        '/',
        '.',
        '']:
  print 's : %s' % (path, os.path.basename(path))

 /one/two/three : three
/one/two/three/ : 
       / : 
       . : .
        : 

import os.path
for path in [ '/one/two/three',
        '/one/two/three/',
        '/',
        '.',
        '']:
  print 's : %s' % (path, os.path.dirname(path))

 /one/two/three : /one/two
/one/two/three/ : /one/two/three
       / : /
       . : 
        : 

for path in [ '/one.txt',
        '/one/two/three.txt',
        '/',
        '.',
        ''
        'two.tar.gz']:

  print '%21s : %s' % (path, os.path.splitext(path))

       /one.txt : ('/one', '.txt')
  /one/two/three.txt : ('/one/two/three', '.txt')
          / : ('/', '')
          . : ('.', '')
      two.tar.gz : ('two.tar', '.gz')

import os.path
paths = [ '/one/two/three',
      '/one/two/threetxt',
      '/one/two/three/four',]
for path in paths:
  print 'PATH:', path

print
print 'PREFIX:', os.path.commonprefix(paths)

PATH: /one/two/three
PATH: /one/two/threetxt
PATH: /one/two/three/four

PREFIX: /one/two/three

import os.path
for parts in [ ('one', 'two', 'three'),
      ('\one', 'two', 'three'),
      ('/one', '/two', '/three', '/four'),]:

  print parts, ':', os.path.join(*parts)

('one', 'two', 'three') : one\two\three
('\\one', 'two', 'three') : \one\two\three
('/one', '/two', '/three', '/four') : /four

import os.path
for path in [ 'one/two/three',
       'one/./two/three',
       'one/../alt/two/three',
       ]:
  print '%20s : %s' % (path, os.path.normpath(path))

    one/two/three : one\two\three
   one/./two/three : one\two\three
one/../alt/two/three : alt\two\three

import os.path
for path in [ '.',
       '..',
       'one/two/three',
       'one/./two/three',
       'one/../alt/two/three',
       ]:
  print '%20s : %s' % (path, os.path.abspath(path))

          . : C:\Users\Administrator\Desktop
         .. : C:\Users\Administrator
    one/two/three : C:\Users\Administrator\Desktop\one\two\three
   one/./two/three : C:\Users\Administrator\Desktop\one\two\three
one/../alt/two/three : C:\Users\Administrator\Desktop\alt\two\three

import os
import time
print 'File:', __file__
print 'Access time:', time.ctime(os.path.getatime(__file__))
print 'Modified time:', time.ctime(os.path.getmtime(__file__))
print 'Change time:', time.ctime(os.path.getctime(__time__))
print 'Size:', os.path.getsize(__file__)

import os.path
filename = r'C:\Users\Administrator\Desktop\tmp'
print 'File    :', filename
print 'Is file?   :', os.path.isfile(filename)
print 'Absoulute  :', os.path.isabs(filename)
print 'Is dir?   :', os.path.isdir(filename)
print 'Is link?   :', os.path.islink(filename)
print 'Mountpoint? :', os.path.ismount(filename)
print 'Exists?    :', os.path.exists(filename)
print 'Link Exists? :', os.path.lexists(filename)

File    : C:\Users\Administrator\Desktop\tmp
Is file?   : False
Absoulute  : True
Is dir?   : True
Is link?   : False
Mountpoint? : False
Exists?    : True
Link Exists? : True

import os
import os.path
import pprint
def visit(arg, dirname, names):
  print dirname, arg
  for name in names:
    subname = os.path.join(dirname, name)
    if os.path.isdir(subname):
      print '%s/' % name 
    else:
      print ' %s' % name
  print
if not os.path.exists('example'):
  os.mkdir('example')
if not os.path.exists('example/one'):
  os.mkdir('example/one')
with open('example/one/file.txt', 'wt') as f:
  f.write('i love you')
with open('example/one/another.txt', 'wt') as f:
  f.write('i love you, two')
os.path.walk('example', visit, '(User data)')

example (User data)
one/

example\one (User data)
 another.txt
 file.txt

#创建文件：
os.mknod("test.txt")    创建空文件
fp = open("test.txt",w)   直接打开一个文件，如果文件不存在则创建文件
 
#获取扩展名：
>>> os.path.splitext('/Volumes/Leopard/Users/Caroline/Desktop/1.mp4')[1:]
('.mp4',)
>>> os.path.splitext('/Volumes/Leopard/Users/Caroline/Desktop/1.mp4')[1]
'.mp4'
 
#获取文件名：
>>> print os.path.basename(r'/root/hahaha/123.txt')
123.txt
>>> print os.path.dirname(r'/root/hahaha/123.txt')
/root/hahaha
 
#判断目录或文件的存在：
>>> os.path.exists('/root/1.py')
True
>>> os.path.exists('/root/')
True
>>> os.path.exists('/root')
True
>>> os.path.isdir('/root')
True
 
#改变工作目录：
>>> os.chdir('/home')
>>> os.getcwd()
'/home'
 
#字符串分割：
>>> '/usr/bin/env'.split('/')
['', 'usr', 'bin', 'env']
 
#获取文件夹大小（Python2.x）：
import os 
from os.path import join, getsize 
  
def getdirsize(dir): 
  size = 0L 
  for root, dirs, files in os.walk(dir): 
   size += sum([getsize(join(root, name)) for name in files]) 
  return size 
  
if __name__ == '__main__':
  filesize = getdirsize('/tmp') 
  print 'There are %.3f' % (filesize/1024/1024), 'Mbytes in /tmp' 
 
#获取文件夹大小（Python3.x）：
import os 
from os.path import join, getsize 
  
def getdirsize(dir): 
  size = 0 
  for root, dirs, files in os.walk(dir): 
   size += sum([getsize(join(root, name)) for name in files]) 
  return size 
  
if __name__ == '__main__':
  filesize = getdirsize('/tmp') 
  print ('There are ' + str(filesize/1024/1024) + 'Mbytes in /tmp')