Re: Format with %-*

[Emanuel Berg <incal@dataswamp.org>]

Michael Heerdegen via Users list for the GNU Emacs text editor wrote:

>> How can I construct a format that uses a space spx followed
>> by a field of width 13 into which I insert a label lbv2.
>
> In Elisp we typically use `string-pad' and
> `truncate-string-to-width'.
>
> It's also possible to add padding with `format' though -
> like in
>
> (format "%10s" "test") -> "      test"

I have made a lot of stuff like the example below.

But never felt 100% about it ...

(defun faster (old new)
  (format "%.1f%%" (* 100 (1- (/ new old 1.0)))) )

;; (faster 0.2  0.5)  ; 150.0%
;; (faster 1.35 0.84) ; -37.8%
;; (faster  200  400) ; 100.0%
;; (faster 1000 1000) ;   0.0%
;; (faster 1000  100) ; -90.0%

(defun percent (nom &optional denom str)
  (or denom (setq denom 1))
  (let ((perc (/ nom denom 0.01)))
    (if str
        (format "%.1f%%" perc)
      perc)))

;; (percent 0.25)           ; 25.0
;; (percent 50 75)          ; 66.66 ...
;; (percent (// 1 2) nil t) ; 50.0%
;; (percent 1019 22 t)      ; 4631.8%

-- 
underground experts united
https://dataswamp.org/~incal