In Dr. Racket, how would I convert a list of strings to a list of list of strings

Question

In Dr. Racket, how would I convert a list containing strings (each string is separated by a space) to a list containing a list of the separated strings. If you can't understand the question too well, here is an example: Given a list like:

(list "abc def" "ghj elm" "ref tio" "pol mnb")

I want to produce:

(list (list "abc" "def") (list "ghj" "elm") (list "ref" "tio") (list "pol" "mnb"))

I wrote up a code for it but I quickly got stuck. Here is my code so far:

(define (a los)
  (cond
    [(empty? los) empty]
    [(char-whitespace? (first los)) (substring (list->string los) 1)]
    [else (a (rest los))]))

For example:

(a (string->list "abc def"))

Produces "def". I was hoping to first separate the strings in the list based on the whitespace and then I would piece them together to form new lists. However, I don't know how to do this. Any tips/hints on how to do this are much appreciated.

Answer 1

There's a built-in procedure called string-split that does just what you need, it's as simple as this:

(define (split-list los)
  (map string-split los))

It works as expected:

(split-list '("abc def" "ghj elm" "ref tio" "pol mnb"))
=> '(("abc" "def") ("ghj" "elm") ("ref" "tio") ("pol" "mnb"))