10. OS

Question 1

os module

Answer 1

os.path.join(‘folder1’,’folder2’,’file.png’)

avoid different system using / or \

Question 2

current working directory

Answer 2

os.getcwd()

Question 3

change directory

Answer 3

os.chdir

Question 4

relative file path

Answer 4

.\ same folder as in cwd

..\ parent folder

Question 5

file path string

Answer 5

1) ‘C:\user\files’

2) r’C:\user\files’

Question 6

converting path to raw string

Answer 6

myVariable = ‘This string is supposed to be raw '
print(r’%s’ %myVariable)

but technically no different on the string after parse

Question 7

check exist

Answer 7

os.path.exists(‘path’)
isfile
isdir

Question 8

break up a path

Answer 8

os. path.dirname()

os. path.basename()

Question 9

whole director

Answer 9

os.listdir

use with isfile

Question 10

create a folder

Answer 10

os.makedirs => create all of the folder

Question 11

open txt file

Answer 11

myfile = open('abc.txt)
myfile = open('abc.txt, 'r')
myfile = open('abc.txt, 'w') -> it creates the file if not exist
myfile = open('abc.txt, 'a') -> it creates the file if not exist

mytext = myfile.read()
myfile.close()

Question 12

shelve module

Answer 12

shelve file is a binary File, very similar to a dictionary.
shelve file has keys and values
can store list

shelfFile = shelve.open(‘mydata’)
shelfFile[‘Cats’] = [‘a’,’b’,’c’]
shelfFile[‘Dogs’] = [‘d’,’e’,’f’]
shelfFile.close()

print(list(shelfFile.keys()))

Question 13

shutil module

Answer 13

shutil. copy (can rename while copy)
shutil. copytree
shutil. move (this is also used for rename)
shutil. rmtree (this will remove the folder and all content)

Question 14

deleting file or path

Answer 14

os. unlink(‘abc.txt’) -> File

os. rmdir(‘my path’) -> remove folder that is empty

Question 15

deleting file or path

Answer 15

os. unlink(‘abc.txt’) -> File
os. rmdir(‘my path’) -> remove folder that is empty

note remove permenantly

Question 16

list of all file and subfolder

Answer 16

os.listdir()

Question 17

send2trash modeul

Answer 17

not basic module

Question 18

walkthrough a folder

Answer 18

for folderName, subfolders, filenames in os.walk(os.getcwd()):
print(folderName)
print(subfolders) -> list of string
print(filenames) -> list of string

Question 19

find all files

Answer 19

for entry in os.scandir(base_dir):
        if entry.is_file():
            yield entry.path
        elif entry.is_dir():
            yield from get_old_files(entry.path)