rpl2a=: ] - (-/ , 0:)@[ {~ {.@[ i. ]
by Hui from
http://www.jsoftware.com/pipermail/programming/2007-July/007303.html is the
most elegant known (to me).
If x and y are from a small domain (e.g. characters), then rpl3a is faster and
leaner: http://www.jsoftware.com/pipermail/programming/2007-July/007302.html
rpl3a=: 4 : 0
'x0 x1'=. x
((x1,a.) {~ (x0,a.) i. ]) y
)
R.E. Boss
> -----Oorspronkelijk bericht-----
> Van: [email protected] [mailto:programming-
> [email protected]] Namens Gian Medri
(...)
> 2) Often I encounter the necessity to replace element x by element y in an
> array.
> I solved the problem in an APL fashion such as:
> repl=: 4 : '($y)$ (1{x) (((0{x)=,y)#i.*/$y)},y' NB. replace x1 in array y by
> x2
>
> This verb works OK for any array, but I wonder if there is a better J-way to
> do
> it.
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