scheme - 评估真假列表

Question

I have a true/false list (like this (#f #f #f #f #f #t)) and I want to loop through it, making an if statement and making appends.

But my map/if iterator does not work as I expected

I`m trying this:

(map (if (false? lst) "do this" "do that" ) lst)

In pseudo code I would have something like this

for each value in lst
  if value
    "do that"
  else
    "do this"

Answer 1

Remember that map receives as parameters a list and a function that operates on each element. Try this:

(map (lambda (e)
       (if (false? e)
           "do this"
           "do that"))
     lst)

For example, if we define lst as '(#f #f #f #f #f #t) the result is:

'("do this" "do this" "do this" "do this" "do this" "do that")