Not 100% sure of what you're asking so if I got this wrong pseudo code it for
me. Remember I am kind of new to racket but I will give it a go:
As I understand it you have a list of lists of strings perhaps like this...
(('this' 'is' 'one')('this' 'is' 'another')....('this' 'is' 'the' 'last'))
and you want to output as such
this is one
this is another
....
this is the last
Ok so here is how I would do this
I will write this as 2 functions, from your main code you call the first
passing it ...
big-list = the whole list of lists
;;in main loop
(per-line big-list)
(define (per-line blist)
(cond
[(empty? blist) #f]
[else
(per-item (first blist))
(newline)
(per-line (rest blist))]))
(define (per-item slist)
(cond
[(empty? slist) #f]
[else
(display (first slist))
(display " ")
(per-item (rest slist))]))
That should be about it. Double check me an ide about matched parens and
brackets. I just eyeballed this real quick in the message. But that is the
approach I would take for a simple proof.
An alternate approach is per-item accepts a string argument and returns the
string to per-line to display. But if the end goal is quick output this is a
bout as concise + readable as I think I can make it.
Ken
On Saturday, October 29, 2016 at 10:27:09 AM UTC-4, meino.cramer wrote:
> Hi,
>
> ...still improving my shortwave-broadcaster-dumper... :)
>
> I have a list with sublists of strings, which I want to concatenate.
> Each sublist shall form one line of output.
> I tried 'string-append', but this gives me something like this
> (excerpt):
> "189RikisutvarpidRas1+20000-24001234567Icelandic"
> ...the separating #\space is missing.
>
> The according code looks like this (excerpt)
>
> (apply string-append sublist)
>
> then I found 'string-join' which has extra-parameters
> to define separator of all kinds.
>
> ...but...how can I express the 'apply'-instruction...with the
> addional parameters???
>
> This looks something inbetween funny and weird:
>
> (apply string-join sublist " ")
>
> and racket mumbles:
> apply: contract violation
> expected: list?
> given: " "
> argument position: 3rd
> other arguments...:
> #<procedure:string-join>
>
>
> ?
>
> Cheers
> Meino
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