Pascal,
Your original solution is perfect for me—I don’t happen to need the index. And
there may in fact be no items with f = 1.
Very clever: it gets a place of honor in the flashcard deck :-).
Many thanks.
Ed
Sent from my iPad
> On Oct 21, 2022, at 12:46 PM, 'Pascal Jasmin' via Programming
> <programm...@jsoftware.com> wrote:
>
> if you want the index rather than the coordinate values, then
>
> (1 i.~ f) y
>
> will "short circuit" to the first 1
>
> and
>
> ({~ 1 i.~ f)
>
> may be faster to get first coordinates than my original solution, though
> errors if there are no items with 1 = f
>
>
>
>
> On Friday, October 21, 2022 at 12:55:41 p.m. EDT, 'Pascal Jasmin' via
> Programming <programm...@jsoftware.com> wrote:
>
>
>
>
>
> }.^:(0 = f@{.)^:_
>
> will return the list with the head being the first f not equal 0.
>
>
>
>
>
>
> On Friday, October 21, 2022 at 12:19:41 p.m. EDT, Ed Gottsman
> <edward.j.gotts...@gmail.com> wrote:
>
>
>
>
>
> Hi. I’m blanking on something basic and research isn’t helping. When the
> blindingly obvious solution is revealed I will blame a combination of sleep
> deprivation and senescence.
>
> I’ve got a long list of coordinates ordered by desirability. I want to
> invoke f (a custom script) with each coordinate in turn. f may return 0
> (failure), in which case I want to invoke it again with the next coordinate.
> When f (eventually) returns 1, I want to terminate—the remainder of the
> coordinates should not be processed. (Note that the very first invocation of
> f may return 1.)
>
> This *almost* feels like ^: in its Do While form. Almost. It also feels
> like SCs around list operations (though they seem to be limited to
> primitives).
>
> Help.
>
> Many thanks.
>
> Ed
>
> Sent from my iPad
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