How to save an updated csv to Google Drive?

I had this issue before:

Changing the content of a google drive file

to change the contents do

my_file = app_files.my_file
csv_file = pandas_csv_file

# set bytes needs a string object... 
my_file.set_bytes(csv_file.get_bytes().decode())

You may also have to do

csv_file = anvil.BlobMedia('text/csv', pandas_csv_file)
my_file.set_bytes(csv_file.get_bytes().decode())

Though note - when I did this I could no longer open the csv in google sheets for some reason - only in docs. It did download as a CSV as expected…

You can check this has worked by going to the file in your google drive, right clicking → manage versions.

edit: corrections