How to map/reduce a list into an alist?

Question

Given a list of things, I want to create an alist by applying a function which creates elements of the alist.

For example, what is the implementation of doit here:

(doit '("a" "b" "c"))
;; => (("a" . "A") ("b" . "B") ("c" . "C"))

You should be more specific in your questions. The answer you accepted does not exactly answer your question. Mine, yes. — gigiair, Apr 16 at 21:39
Thank you for feedback @gigiair. But My question is how to to create an alist. The example with the doit function was just an example to make my question more clear. The answer from @jagrg is just perfect. It captures the essence of the problem here. — Witek, Apr 17 at 8:55

jagrg · Accepted Answer · 2023-04-16 21:06:40Z

2

mapcar is another option:

(mapcar (lambda (x)
          (cons x (upcase x)))
        '("a" "b" "c"))

answered Apr 16 at 21:06

jagrg

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shynur · Accepted Answer · 2023-04-17 07:57:48Z

1

It can be

(defun doit (l)
  (seq-map (lambda (x)
             (cons x (upcase x))) l))

shynur

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answered Apr 16 at 21:04

gigiair

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What is the advantage of using seq-map over mapcar? ( seq-map defined in seq.el.gz seems to be only a wrapper to mapcar)
– Claudio
Apr 16 at 22:49
1

seq-map operates on sequences of any type.. It is not just a wrapper.
– gigiair
Apr 17 at 5:32
@Claudio: deleted
– shynur
Apr 17 at 14:53

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2 Answers 2