How to format a string variable to only show the first x number of characters?

Question

I have a string variable, specifically the emacs-version variable that can be quite long and I am only using message with the first 4 of those characters.

Is there a way to format the variable in a message statement so that I am only printing the first x number of characters?

Right now I am using substring but it seems like there should be an easier / cleaner way. Please let me know if there is a more efficient way to do this:

(message "You are running version %s old." (substring emacs-version 0 4)))

Answer 1

C-hf format tells you:

For %s and %S, the precision specifier truncates the string to the given width.

Hence:

(format "%.4s" emacs-version)

Answer 2

In this case, I'd recommend resorting to emacs-major-version and emacs-minor-version:

(message "emacs version %s.%s" emacs-major-version emacs-minor-version)