The Python OS module

The os module is a module provided by Python whose purpose is to interact with the operating system, it thus makes it possible to manage the tree structure of files, to provide information on the operating system processes, system variables, as well as many system features… The os module can be loaded simply with the command: import os

1- The os.getlogin() method 

os.getlogin (): returns the current user name. Example. Python program that returns the username:

import os
user = os.getlogin ()
print (user) # prints the username

2-The os.mkdir() method 

os.mkdir(path): creates a directory corresponding to the specified path. Example. creation of a folder at the root of the disk C:\

import os
os.mkdir ("c:/myFolder") # creates a folder named myFolder on disk C:\

3- The os.getcwd() method 

os.getcwd(): returns the current directory as a string character. Example:

import os
current_dir = os.getcwd ()
print (current_ rep) # returns the current directory

4- The os.path method 

 In order to use the os.path method, you must first import the pathlib module. The pathlib module is a module with an object-oriented interface included in python since 3.4 version with very intuitive methods allowing to interact with the file system in a simple and user-friendly way.

4.1- Test if a directory exists with the os.path.exist() method 

The os.path.exist() method is used to test whether a directory exists or not Example. test the existence of a directory

import os
from pathlib import Path
print (os.path.exists( "c:/users/"))
#display True
# ---------------------------
# We can also use
print(not os.path.exists("c:/users/"))
#display false 

4.2- Test if a path is a directory or a file with the is_dir() and is_file() methods. 

To test the nature of a path if it is a directory or a file, we use the is_dir() and is_file() methods:

Example

import os
from pathlib import Path
myDirectory = "C:/Users"
p = Path(myDirectory)
print(p.is_dir()) # displays True
print(p.is_file()) # display False

Example

import os
from pathlib import Path
myDirectory = "C:/Windows/system.ini"
p = Path(myDirectory)
print (p.is_dir()) # display False
print (p.is_file()) # displays True

4.3- Find the absolute path using the absolute() method

The absolute() method returns the absolute path of the file that contains the python code. We will make a small test by creating a python file which contains the code below and save it on the desktop:

Example.

# find absolute path
import os
from pathlib import Path
myDirectory = "."
p = Path (myDirectory)
print (p.absolute ())
# Displays: "C:\Users\acer\Desktop"

4.3- Determination of the absolute path using the absolute() method 

The absolute() method returns the absolute path of the file that contains the python code. We will give a small test by creating a python file which contains the code below and save it on the desktop:

Example.

# find absolute path
import os
from pathlib import Path
myDirectory = "."
p = Path (myDirectory)
print (p.absolute ())
# Displays: "C:/Users/acer/Desktop"

4.4- Transform a path into an uri address with the as_uri() method 

The as_uri() method is used to transform a path into uri (uniform resource identifier) Example

from pathlib import Path
myDirectory = "C:/Users/Public/Videos/Sample Videos/Wildlife.wmv"
p = Path (myDirectory)
print (p.as_uri())
# Displays: file: ///C:/Users/Public/Videos/Sample%20Videos/Wildlife.wmv

4.5 Obtaining the path of the parent folder with the parent method 

The parent() method returns the parent folder of an existing folder: Example. parent folder

from pathlib import Path
myDirectory = "C:/Users/Public/"
p = Path (myDirectory)
print (p.parent) # Displays 'C:/Users'
# parent also returns the parent folder of a file
myDirectory = "C:/Users/Public/Videos/Sample Videos/Wildlife.wmv"
p = Path (myDirectory)
print (p.parent) # Displays 'C:/Users/Public/Videos/Sample Videos'

4.6- Retrieving the contents of a folder with the scandir() method applied to the Path() method 

 By applying the scandir() method to the Path() method, you can get the contents of a folder: Example: retrieving the contents of the directory 'C:/Users'

from pathlib import Path
import os
mydirectory = "c:/users"
p = Path (myDirectory)
for x in os.scandir (p):
    print (x)

Which displays:

4.7 Display all files with a specific extension via the glob() method 

The glob() method is one of the methods of the Path object used to display the list of files with a given extension: Example: display of .dll libraries in the 'C:/Windows' directory

from pathlib import Path
p = Path ('C: / Windows /')
for f in list (p.glob ('** / *. dll')):
print (f)

Note 

For more details on the Path module see the official documentation: https://docs.python.org/3.0/library/os.path.html

Younes Derfoufi
my-courses.net