Rounding percentages... was setq-default

[Jean Louis]

* Emanuel Berg via Users list for the GNU Emacs text editor 
<help-gnu-emacs@gnu.org> [2021-04-19 20:28]> > Let us say there are 2 buffers, 
you wish to mark 3 people
> > in the list in one buffer and 4 people in the list in other
> > buffer, but you don't want to mix them. Their marks go into
> > individual or buffer local variables that are named same
> > but are different from buffer to buffer. [...]
> 
> This is what you do for a living, move people
> between buffers?

I also may move goods from buffer to buffer.

> But I also have lists of people, .mailrc is one, the other is
> a NOC list (Non-Official Cover list) of people climbing in
> our tree house [1] - without here being tricked into letting
> the authorities score an easy win by me disclosing the list,
> let me say that it is a possibility that we currently have 57
> people climbing, 52% from se, 16 nationalities, 54% females.

(defun pct-of-number-in-total (number total)
  "Return the percentage that NUMBER represents in a TOTAL."
  (/ number total 0.01))

(defun pct-of-number-in-total-1 (number total)
  "Return the percentage that NUMBER represents in a TOTAL."
  (let* ((number (+ number 0.0))
         (total (+ total 0.0))
         (percent (/ total 100.0))
         (percentage (/ number percent 100)))
    percentage))

(defun pct-list (list)
  "Return list that representes percentages of values in a given LIST."
  (let* ((total (apply '+ list)))
    (mapcar (lambda (item) (pct-of-number-in-total item total)) list)))


(pct-list '(31 26)) ⇒ (54.385964912280706 45.614035087719294)

I am not sure how do you get 54% females, maybe one of them is round?

(pct-list '(30 27)) ⇒ (52.63157894736842 47.368421052631575)

The round one must be coming from Sweden according to above math.


-- 
Jean

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