Add files via upload

Python/ch4.File Handling/Work with OS.txt

@@ -0,0 +1,16 @@
+commands:
+- getcwd() # getting pointer address
+- chdir() # change pointer address
+- listdir() # contents of current address like as: list of all files and folders
+- mkdir() # creating new folder
+- rmdir() # removing an empty folder
+- remove() # removing a file
+- rename() # transfer a file to another directory
+- system() # running directly system commands in python terminal
+- walk() # finding all files of a folder
+- path.exists() # existense of a file/folder
+- path.isfile() # found is input a file?
+- path.isdir() # found is input a folder?
+- path.basename() # giving file name of input address
+- path.join() # concat of some strings of name from input to output
+- path.commonprefix() # giving longest common prefix of input in output

Python/ch4.File Handling/Work with OS_1.py

@@ -0,0 +1,8 @@
+>>> import os
+>>> os.getcwd()
+'/home/mohamadreza/Desktop/python/os_sample'
+>>> os.listdir()
+['codes', 'README.md', 'data', 'images']
+>>> os.chdir('codes')
+>>> os.listdir()
+['test.py', 'project', 'model.py', 'main.py']

Python/ch4.File Handling/Work with OS_10.py

@@ -0,0 +1,8 @@
+>>> os.path.commonprefix(['project/test.py', 'project/main.py'])
+'project/'
+>>> os.path.commonprefix(['project/data/test.py', 'project/data/main.py'])
+'project/data/'
+>>> os.path.commonprefix(['project/data/test.py', '../main.py'])
+''
+>>> os.path.commonprefix(['project/data','modules/data'])
+''

Python/ch4.File Handling/Work with OS_2.py

@@ -0,0 +1,12 @@
+>>> os.mkdir('images/other')
+>>> os.mkdir('images/other/2019')
+>>> os.listdir('images/other')
+['2019']
+>>> os.rmdir('images/other')
+Traceback (most recent call last):
+  File "<stdin>", line 1, in <module>
+OSError: [WinError 145] The directory is not empty:
+'/home/ali/Desktop/python/os_sample/images/other'
+>>> os.rmdir('images/other/2019')
+>>> os.listdir('images/other')
+[]

Python/ch4.File Handling/Work with OS_3.py

@@ -0,0 +1,4 @@
+>>> os.remove('model.py')
+>>> os.listdir()
+['project', 'test.py', 'main.py']
+>>> os.remove('../images/animal/ant.png')

Python/ch4.File Handling/Work with OS_4.py

@@ -0,0 +1,12 @@
+>>> os.rename('test.py', 'model.py')
+>>> os.listdir()
+['project', 'model.py', 'main.py']
+>>> os.rename('model.py', 'project/model.py')
+>>> os.listdir()
+['project', 'main.py']
+>>> os.rename('main.py', 'project/a.py')
+>>> os.listdir()
+['project']
+>>> os.listdir('project')
+['control.py', 'a.py', 'view.py', 'model.py']
+>>> os.system('python codes/main.py')

Python/ch4.File Handling/Work with OS_5.py

@@ -0,0 +1,7 @@
+>>> w = os.walk('.')
+>>> type(w)
+<class 'generator'>
+>>> list(w)
+[('.', ['project'], ['main.py']), ('./project', [], ['control.py', 'a.py', 'view.py', 'model.py'])]
+>>> list(os.walk('..'))
+[('..', ['codes', 'data', 'images'], ['README.md']), ('../codes', ['project'], ['main.py']), ('../codes/project', [], ['control.py', 'a.py', 'view.py', 'model.py']), ('../data', [], ['secrets.txt', 'python.txt']), ('../images', ['animal'], []), ('../images/animal', [], ['ant.jpg', 'dog.png', 'cat.jpg'])]

Python/ch4.File Handling/Work with OS_6.py

@@ -0,0 +1,6 @@
+>>> os.path.exists('project')
+True
+>>> os.path.exists('project/model.py')
+True
+>>> os.path.exists('sample.py')
+False

Python/ch4.File Handling/Work with OS_7.py

@@ -0,0 +1,7 @@
+# found to file or folder with isfile() and isdir()
+>>> os.path.isdir('project')
+True
+>>> os.path.isdir('project/view.py')
+False
+>>> os.path.isfile('project/view.py')
+True

Python/ch4.File Handling/Work with OS_8.py

@@ -0,0 +1,10 @@
+>>> os.sep
+'/'
+>>> '../main/images'.split(os.sep)
+['..', 'main', 'images']
+>>> os.path.basename('project/control.py')
+'control.py'
+>>> os.path.basename('../images/animal/cat.jpg')
+'cat.jpg'
+>>> os.path.basename('../main/images')
+'images'

Python/ch4.File Handling/Work with OS_9.py

@@ -0,0 +1,4 @@
+>>> os.path.join('..', 'images', '2019')
+'../images/2019'
+>>> os.sep.join(['..', 'images', '2019'])
+'../images/2019'