And we wonder why newcomers find J challenging!
To paraphrase Spiderman's uncle: 'With great power, comes a steep learning
curve'
Thanks so much for these examples. My early experiences with Insert (/)
developed my concepts of how rank _1 would look, except that its actual rank is
_ (this is consistent with your first line regarding f"(_N) is really f"(_N)"_
if I understand correctly).
Clearly, animating an accurate, comprehensive and understandable visual for
Rank (") will be an adventure.
Cheers, bob
On -Mar12-2010, at -Mar12-20109:26 AM, Dan Bron wrote:
> bob therriault wrote:
>> I have not found any primitives that have a built in rank of _1 (items).
>
> For several reasons, you won't see any primitives with an explicit rank of
> _1. For one thing, f"(-N) is really f"(-N)"_ which
> would mess with @ and other functional calculus.
>
> So verbs with unbounded rank are good suspects for "item users". Consider:
>
> ~. y Unique items
> ~: y Unique items (as boolean mask)
> = y Self-classify items
> ,. y Ravel items of y
>
> x -. y Exclude items of x that are cells of y
> x i. y x i: y x I. y Index of items of x in y
>
> ;: Parse items of y
> {. {: }. }: Take/drop items of y
> A. C. Permutations of items of y
> e. Membership in [opened] items of y
> # Count/filter items of y
>
> But it's not just verbs with are item-oriented. Consider:
>
> u/ y Dyad u between items of y
> u;.n y Cut items of y
> u/.y Classify items of y
>
> x u/. y Classify items of y
>
> /: \: Grade/sort the items of y
> u\y u\. Affixes of the items of y
>
> And it gets stranger yet. Consider:
>
> m`:3 y Insert items of m between items of y cyclically (m/ y)
> f...@g f&g f&.g Apply f to each "item" of g
> (indirect)=.y Assign names to items
>
> Items, items, everywhere, nor any _1 to rank.
>
> -Dan
>
>
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