Re: bike shifting - output decimal in percent

[Emanuel Berg <moasenwood@zoho.eu>]

>> (format "%2.2g%%" (* 100.0 foo)) => "31%"
>
> Great, thanks a lot :)

Oups, spoke (no pun intended :)) too soon.
Too much respect for Drew, I suppose ;)

But to be honest, the original program is
_much_ better. Check out the examples below:

;; secret bonus program :)
;; thanks to friend at #emacs
(defun percent-string (decimal)
  (concat
   (number-to-string
    (round (* 100 decimal)) ) "%") )
;; test: (percent-string 0.42857142857142855) ; "43%"

(defun bike-compute-step (from to)
  (percent-string
   (/ (- from to)
      from
      1.0) ))
;; test - should be 43% for
;; one 42t and one 24t chainring
;; according to an article in the spring 2019 issue
;; of "Bicycle Quarterly" (ISSN 1941-8809) -
;; (bike-compute-step 42 24) ; "43%"

;; (percent-string 0.01)  ; "1%"
;; (percent-string 0.1)   ; "10%"
;; (percent-string 1)     ; "100%
;; (percent-string 2)     ; "200%"

;; (format "%2.2g%%" (* 100.0 0.01)) ; " 1%"    (?)
;; (format "%2.2g%%" (* 100.0 0.1))  ; "10%"
;; (format "%2.2g%%" (* 100.0 1))    ; "1e+02%" (!?)
;; (format "%2.2g%%" (* 100.0 2))    ; "2e+02%" (...)


File: https://dataswamp.org/~incal/emacs-init/bike.el

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