Python判断文件和文件夹是否存在的方法(最新推荐)

>>> import os
>>> os.path.exists('d:/assist')
True
>>> os.path.exists('d:/assist/getTeacherList.py')
True
>>> os.path.isfile('d:/assist')
False
>>> os.path.isfile('d:/assist/getTeacherList.py')
True
>>> os.makedirs('d:/assist/set')
>>> os.path.exists('d:/assist/set')
True

import os
filename = r'/home/tim/workspace/test.txt'
if os.path.exists(filename):
    message = 'OK, the "%s" file exists.'
else:
    message = "Sorry, I cannot find the "%s" file."
print message % filename

>>> import os
>>> os.path.exists(r'C:\1.TXT')
False
>>> 

$ python
Python 2.7.3 (default, Jan  2 2013, 16:53:07) 
[GCC 4.7.2] on linux2

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

>>> import os
>>> 

>>> 

>>> tobecheckdir = r'/home/tim/workspace'

>>> os.path.isdir(tobecheckdir)

True
>>>

from os import path, access, R_OK  # W_OK for write permission.
PATH='./file.txt'
if path.exists(PATH) and path.isfile(PATH) and access(PATH, R_OK):
    print "File exists and is readable"
else:
    print "Either file is missing or is not readable"

def file_exists(filename):
    try:
        with open(filename) as f:
            return True
    except IOError:
        return False

import os 
os.path.isfile('test.txt') #如果不存在就返回False 
os.path.exists(directory) #如果目录不存在就返回False

>>> from ftplib import FTP
>>> f = FTP('ftp.python.org')
>>> f.login('anonymous', 'guido@python.org')
'230 Guest login ok, access restrictions apply.'
>>> f.dir()

f.retrbinary('RETR %s' % FILE,open(FILE, 'wb').write)
except ftplib.error_perm:
print 'ERROR: cannot read file "%s"' % FILE 40 os.unlink(FILE)