文件和目录是否可写

writeable.py

import os
import tempfile

def dir_writeable(dir):
    try:
        (fd, name) = tempfile.mkstemp(dir=dir)
        os.close(fd)
        os.unlink(name)
    except IOError:
        return False
    return True

def file_writeable(filename):
    return os.access(filename, os.W_OK)