On Wed, Aug 10, 2016 at 5:50 AM, Greg Hendershott <greghendersh...@gmail.com
> wrote:
> > I feel like there should be a simpler way to do this, but I haven't found
> > one despite much Googling and reading of docs about "for" and its
> siblings.
> > Can someone point me the right way?
> >
> > I'd like to be able to iterate over a list N elements at a time -- e.g.,
> > grab elements 1 and 2, do something with them, grab 3 and 4, etc.
> >
> > This will do the job, but I suspect there's a more built-in way:
> >
> > (define data '(("foo") ("bar") ("baz") ("jaz") ("quux") ("glug")))
>
> racket/sequence provides an `in-slice` sequence to use with `for` forms:
>
> https://docs.racket-lang.org/reference/sequences.html#%
> 28def._%28%28lib._racket%2Fsequence..rkt%29._in-slice%29%29
>
in-slice produces lists of N elements, so I guess if I wanted to iterate
over every 2nd element I would use something like this?:
(define data '(("foo") ("bar") ("baz") ("jaz") ("quux") ("glug")))
(for ((x (~> data
in-list
(in-slice _ 2)
(map car))))
...do something...)
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