python - summary with code on path operation

in this post, we are going to discuss the topic of path operation, the path operation here include 

•  os.path.join
•    os.path.split
•    os.path.splitext
•    os.path.basename
•    os.path.commonprefix
•    os.path.expandvars
•    os.path.isdir
•    os.listdir
• and constants
•    os.pardir
•    os.curdir
•    os.path.exists
•    os.path.isfile

Path operation is something that we come across daily and in this post, thing that is not covered include how to open/write/close files. 
here is the details with code summary. 

'''
Created on 2012-11-8

@author: Administrator
file: PathOperation.py 
description: this file will demonstrate the use of path operations, such as the 
   os.path.join
   os.path.split
   os.path.splitext
   os.path.basename
   os.path.commonprefix
   os.path.expandvars
   os.path.isdir
   os.listdir
and constants
   os.pardir
   os.curdir
   os.path.exists
   os.path.isfile
      
'''

import os

def path_join():
    print(os.path.join('bin', 'utils', 'disktools'))
    
def path_split():
    print(os.path.split(os.path.join('some', 'directory', 'path')))

def path_basename():
    x = os.path.basename(os.path.join('some', 'directory', 'path.jpg'))
    print(x)
def path_dirname():
    x = os.path.dirname(os.path.join('some', 'directory', 'path.jpg'))
    print(x)

def path_common_prefix():
    path1 = os.path.join("some", "directory")
    path2 = os.path.join("some", "another_directory")
    x = os.path.commonprefix([path1, path2])    
    print(x)

def path_pardir():
    path = os.path.join(os.curdir, os.pardir, os.pardir)
    x = os.path.isdir(path)
    print(x)

def path_curdir():
    x = os.listdir(os.curdir)
    print(x)

def os_name():
    if os.name == 'posix':
        root_dir = '/'
    elif os.name == 'nt':
        root_dir = "C:\\"
    else:
        print("dont' understand this operating system")

def path_exists():
    x = os.path.exists('c:\\users\\Administrator\\umbrella0.txt')
    print("*** os.path.exists", x)    
def path_isfile():
    x = os.path.isfile('c:\\users\\Administrator\\umbrella0.txt')
    print("*** os.path.isfile", x)
        
if __name__ == '__main__':
    path_join()
    path_split()
    path_basename()
    path_common_prefix()
    path_pardir()
    path_curdir()
    os_name()

We may come back to file and directory operation later .

One thing that we might have found on the above code is that there is a glob.glob method that is to bridge the gap of windows shell and the linux shell, where the linux shell (cshell, bash, sh) all have the ability to preprocess the wildcards * to files that matches the patterns. while the * is passed in as verbatim to the windows shell.