fromx=: 1 : '(m,~]) {~ i...@#@] i. ['
3 1 4 1 5 9 'X' fromx 'abcdef'
dbebfX
3 1 4 1 5 9 (_1) fromx i.6 4
12 13 14 15
4 5 6 7
16 17 18 19
4 5 6 7
20 21 22 23
_1 _1 _1 _1
Handling of negative indices left as an exercise for the reader.
----- Original Message -----
From: "Alan K. Stebbens" <[email protected]>
Date: Thursday, September 3, 2009 7:50
Subject: Re: [Jchat] wishlist adverb: ignore indices
To: Chat forum <[email protected]>
> On Sep 3, 2009, at 3:34 AM, Raul Miller wrote:
>
> > I often wish that I had an adverb which would let me index beyond
> > array boundaries (getting fill elements). I expect that
> this would
> > also work on verbs based on intervals (such as dyads using \
> and some
> > dyads using ;.), extending their boundaries in a reasonable fashion.
>
> In most OO languages, it's possible to override the standard
> indexing
> to accomplish specific requirements as needed for a given matrix-
> like,
> array-like or hash-like object, including defining a "fill"
> attribute,
> and indexing semantics.
>
> What is the comparable J method for accomplishing this?
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