1. Basic Operation of Files

def open(file, mode='r', buffering=None, encoding=None, errors=None, newline=None, closefd=True): 

1. Format One

   • open

     file1 = open('demo1.txt','r')
     

   • operation

     file1.write('Hello Python !')
     

   • Close

     file1.close()
     

2. Format 2

   • Open, operate, close within a structure (automatically close when finished)

     with open('demo1.txt','r') as file1:
         file1.write('Hello Python !')
     

2. Reading and Writing Mode

1. Copy the contents of a file

   • Read, assign a variable to extract data

     with open('demo1.txt','r') as file1:
         data = file1.read()   
     

   • Write the variable to complete the replication

     with open('demo2.txt','w') as file2:
         file2.write(data)
     

2. Graphic data (picture.jpg) or video data (video.mp4)

   'rb': Hinder  b  Represents the meaning of bytes, because binary data is stored directly in graphics and videos
   'wb'
   'ab'
       
   

3. Read and write plus

   'r+'   'w+'   'a+'
   'rb+'  'wb+'  'ab+'
   

3. Read and write operations

1. Read All

   #The contents of the'hello.txt'file
   hello
   hello hello
   hello hello hello
   
   #The code is as follows
   with open('hello.txt','r') as file1:
       data = file1.read()
       print(data)
   

   It will output in full format, but the disadvantage is that it consumes too much memory and can be solved in three ways

2. Read with parameters

   with open('hello.txt','r') as file1:
       data = file1.read(7)
       print(data)
   
   #The output format is as follows: where a line break or space is also considered a character
   hello
   h
   

   If batch reading is required, the Convention parameter value is 1024

3. Single Line Read

   with open('hello.txt','r') as file1:
       data = file1.readline()
       print(data)
   
   #The output format is as follows
   hello
   

4. Multiline Read

   with open('hello.txt','r') as file1:
       data = file1.readlines()
       print(data)
   
   #The output format is as follows
   ['hello\n', 'hello hello\n', 'hello hello hello\n']
   

   The data is output as a list, with one element per line, including line breaks

5. During copying files: write() corresponds to read(), writelines() corresponds to readlines()

6. File Path

   • Absolute path: Start with a drive letter and write out the detailed path

     with open('F:\Python\Python Basic knowledge learning\Python Course Practice Exercise\demo1.txt','w') as file1:    file1.write(' hello world , hello python ')
     

   • Relative path: Read or create new files at the same directory level using the current location as a reference value

     with open('.\..\..\demo1.txt','w') as file1:    file1.write('hello python 2021')    with open('.\Practice\demo1.txt','w') as file1:    file1.write('hello python 2021')#       .\  :  Represents the directory at this level#       ..\ :  Represents the directory above the current directory#   \Exercise\: Represents writing under the Exercises folder in the current folder
     

IV. OS Modules

• Function name	Explain
  rename (file 1, file 2)	File rename: change the name of file 1 to file 2
  remove (file name)	Delete Files
  mkdir (directory name)	Create directory
  Rmdir (directory name)	Delete Directory
  ...	...

1. Import OS modules

   import os
   

2. File rename with file location change

   os.rename('demo1.txt','.\..\demo2.txt') #Change the file name of demo1 to demo2 and move to the last directory
   

3. Delete Files

   os.remove('.\..\demo2.txt')
   

4. Create directory

   os.mkdir('.\..\Practice')
   

5. Delete Directory

   os.rmdir('.\..\Practice')