In python3, the file input and output features, and how to overwrite the file content and the next input,

In python3, the file input and output features, and how to overwrite the file content and the next input,

Today I met a very interesting python feature. Originally, I wanted to open a file and input some content at the end of the file. The Code is as follows:

f = open('test.txt', 'r+')f.write(content)f.close()

The result shows that no matter what I write, the content is always written from the beginning of the file and overwrites the original content. I checked the official documentation and did not know how to do it.

But by accident, I found the method of writing to the end. The Code is as follows:

f = open('test.txt', 'r+')f.read()f.write(content)f.close()

Yes, just adding a row of f. read (), your write function will automatically be written to the end. After reviewing the official documentation, it seems that this is not mentioned.

 
 

  
  
 
   read( 
   size) 
  
  
  
 
   
Read and return at most size characters from the stream as a single str. If size is negative or None, reads until EOF.
 
  
 
 

 

 
 

  
  
 
   
 
    
 
     write( 
     s) 
    
 
    
 
     
Write the string s to the stream and return the number of characters written.