file.truncate()

Question

what does file.truncate() exactly do ?

Answer 1

It truncates everything past what you have already read.

https://www.tutorialspoint.com/JUMP_LINK__&&__python__&&__JUMP_LINK/file_truncate.htm

Answer 2

...and one way people use it is to immediately 'zero' a file without actually deleting it (and then losing its name or position in the file system); sometimes specifically because it's faster.