MAP (and variants) vs LOOP - Popular opinion observation?

[B. Pym]

Then suppose you later need the loop/map to collect some of the values
under certain conditions. You might have
(loop for x in (get-list)
for i from 0
do (format t "~A - ~A~%" i x)
if (test x)
collect (foo x))

Gauche Scheme

(use srfi-13) ;; string-upcase

(filter-map
(lambda (x i) (print i " - " x)
(and (string? x) (string-upcase x)))
'(foo "an" 8 "why")
(lrange 0))

0 - foo
1 - an
2 - 8
3 - why
("AN" "WHY")

[B. Pym]

Post by B. Pym

Then suppose you later need the loop/map to collect some of the values
under certain conditions. You might have
(loop for x in (get-list)
for i from 0
do (format t "~A - ~A~%" i x)
if (test x)
collect (foo x))

Gauche Scheme
(use srfi-13) ;; string-upcase
(filter-map
(lambda (x i) (print i " - " x)
(and (string? x) (string-upcase x)))
'(foo "an" 8 "why")
(lrange 0))
0 - foo
1 - an
2 - 8
3 - why
("AN" "WHY")
Suppose you have
(loop for x in (get-list)
do (format t "~A~%" x))
and then it turns out you need to print a numeric index. You can do
(loop for x in (get-list)
for i from 0
do (format t "~A - ~A~%" i x))
If you start with
(mapc (lambda (x) (format t "~A~%" x)) (get-list))
it seems (to me) that it'd be harder to modify it as needed,
(let ((list (get-list)))
(mapc (lambda (i x) (format t "~A - ~A" i x))
(range 0 (length list))
list))
(I'm assuming the toolkit includes a RANGE utility, or something similar.)

Gauche Scheme

Shorter than the loop:

(for-each
(pa$ format #t "~a - ~a\n")
(lrange 0)
'(a b c))

0 - a
1 - b
2 - c