[racket-users] For/lists: where is #:continue?

Hello users, What is the proper design pattern to skip invalid values when using for/list? The programs below fails because #:continue is not recognized: for/list ([i (in-range 0 1000)]) (let ((value (vector-ref vector i))) (if ( 0 (length value)) value #:continue)))

Re: [racket-users] For/lists: where is #:continue?

I think you're looking for #:when / #:unless. On Mon, Jul 13, 2015 at 3:12 PM, Pekka Niiranen pekka.niira...@pp5.inet.fi wrote: Hello users, What is the proper design pattern to skip invalid values when using for/list? The programs below fails because #:continue is not recognized:

Re: [racket-users] For/lists: where is #:continue?

Also, since you're not actually interested in the value of i, you should probably use in-vector rather than in-range. The whole example would be: (for/list ([value (in-vector vector)] #:when ( 0 (length value))) value) On Mon, Jul 13, 2015 at 3:18 PM, Jon Zeppieri

Re: [racket-users] For/lists: where is #:continue?

In that case, you probably want to make use of in-value to bind single-value sequences in your for*/list: (for*/list ([(start end) (in-parallel 1 1000)] [i (in-range start (sub1 end))] [s (in-value (vector-ref vector i))] [columns (in-value (string-split s ,))]