My original path data 'd' has 5 digits after the decimal points but after I applied the path.to_relative(), the path data rounded to 3 digits after the decimal points. I was wondering if it is possible to retain the 5 digits after the decimal points when converting the d using path.to_relative() or path. to_absolute functions. 

Thanks!

I just noticed that I have posted multiple same posts, I didn't mean to do that. Sorry for it!

I'm not sure about that one, I think it comes from Vector2d()

You would have to ask that question in https://chat.inkscape.org/channel/inkscape_extensions

Thanks, should I ask the questions in the channel of team_vector? 

No, the link above, 'inkscape_extensions'

Okay, doctormo and joneuhauser answered in the chat :) -  Many thanks.

The answer is to set the inkex number template

https://inkscape.gitlab.io/extensions/documentation/source/inkex.paths.html?highlight=number_template#inkex.paths.PathCommand.number_template

for path_object in selection_list:
    inkex.paths.PathCommand.number_template = '{:.2f}';
    inkex.errormsg(path_object.path.to_absolute())
    inkex.paths.PathCommand.number_template = '{:.6f}';
    inkex.errormsg(path_object.path.to_relative())

If you type "python number template" into google, there are lots of examples of different number template settings - not sure if all are supported :)

Thanks!