Hello lads!




I'm having some trouble with file management in Python and I'm hoping someone here can help me.




I'm working on a script that reads and writes data to a file. The problem is that when I try to write data to the file, it seems to overwrite the existing content instead of adding to it. Here's a simplified version of my code:

# Writing to a file
with open('data.txt', 'w') as file:
    file.write('New content')

I'm using "w" mode because I want to make sure the file is updated with the latest content. However, I expected it to overwrite the content, not add it. I thought "w" mode was supposed to handle this, but it looks like it might do the opposite.




I also check this: http://www.python.it/forum/thread/6940/lettura-di-un-file-csv-da-google-sheetsgenerativeai But I didn't find any solution. Could someone point me to the best solution for this? Can someone explain if this is the expected behavior or if I might be misunderstanding how the file modes work? Also, what would be the correct mode if I wanted to add content without overwriting existing data?




Thanks in advance for any help!

Hey there!

It looks like there's a bit of confusion about the file modes in Python.

- w: Opens the file for writing. If the file already exists, it overwrites the existing content. If the file does not exist, it creates a new one. This is what is happening in your script: you are overwriting the entire content of the file with the string 'New content'.

- a: Opens the file in append mode. If the file exists, the new content is added to the end of the file, without overwriting the existing content. If the file does not exist, it creates a new one.
If you want to add content to the file without overwriting what's already there, you should use the 'a' (append) mode instead of 'w'.

Here’s how your code could look:

# Adding content to a file
with open('data.txt', 'a') as file:
    file.write('New content\n')

Have fun.

When you open a file with the "w" mode, it deletes the existing content and writes new data, so your behavior is expected. If you want to add content without overwriting the old data, you should use the "a" (append) mode. Here’s how to modify your code:


# Appending to a file
with open('data.txt', 'a') as file:
file.write('New content\n')


Good luck!

Hi!
The "w" mode in Python actually does exactly what you're describing—it overwrites the existing file content every time it's opened. If you want to add to the file without erasing what's already there, you need to use "a" for append mode. "a" will keep the old content and add your new content to the end of the file.



--- Ultima modifica di Dan Calderon in data 2024-11-07 09:59:14 ---

--- Ultima modifica di Dan Calderon in data 2024-11-07 09:59:56 ---

Hi, but two posts to write more or less the same thing I had already written, and even worse than how I wrote it?

Come on guys (or bots), let's collaborate a bit and not create unnecessary background noise.

Cya