Query regarding sys.stdout.write

[Chris Angelico]

On Mon, Jun 8, 2015 at 7:17 AM, Sreenath Nair <sreenath.cg at gmail.com> wrote:
> I have a general query about the following snippet:
>
> import os
> Import sys
> for each_dir in os.listdir("/home/tmpuser"):
>     full_path = os.path.join("/home/tmpuser", each_dir)
>     sys.stdout.write("\r%s" % full_path)
>     sys.stdout.flush()
>
> The snippet is a simplified example of me trying to print to the same line
> by using carriage return. This is working fine. However, the issue is that
> if the previous line was longer than the current line being printed then
> there are characters leftover from the previous print. Like so:
>
> Print no. 1: /home/tmpuser/somedir/somefile.ext
> Print no. 2:/home/tmpuser/somefile.extmefile.ext
>
> In case of the newly printed shorter line, the characters from the
> previously printed longer line are leftover... Is there any way to clear the
> previous print? While still being able to print to the same line?

The most common solution is to print out some spaces to overwrite the
previous text. It's simple, straight-forward, and works on all
systems. But if your console is properly ANSI-compliant, you may be
able to simply append \33[K to clear to end of line:

https://github.com/Rosuav/LetMeKnow/blob/master/letmeknow.py#L172

No need to retain the previous line length, no need to guess at the
length required, and no lengthening the long lines (which annoyed me;
I had to make the console window X characters wider than it needed to
be, else the spaces would make it wrap). Give it a try, see what
happens; worst case, fall back on what Cameron suggested.

ChrisA