On Thu, 21 Sep 2006, Roger Hui wrote:
> v^:u
>
Beware of the fact that anything nonzero is "true",
so this (delightful!) idiom won't always be equivalent to
Pascal's UpdateWhere:
NB. begin J session
NB.
UpdateWhere=: 2 : 'if. u y do. v y else. y end.'
(>&0 UpdateWhere *:)"0 i: 3
_3 _2 _1 0 1 4 9
(* UpdateWhere *:)"0 i: 3
9 4 1 0 1 4 9
(] UpdateWhere *:)"0 i: 3
9 4 1 0 1 4 9
(*:^:(>&0))"0 i: 3
_3 _2 _1 0 1 4 9
(*:^:*)"0 i: 3
0j1.73205 0j1.41421 0j1 0 1 4 9
(*:^:])"0 i: 3
1.05988j0.439015 0.840896j0.840896 0j1 0 1 16 6561
NB.
NB. end J session
Regards, Ewart Shaw
>
>
> ----- Original Message -----
> From: Pascal Jasmin <[EMAIL PROTECTED]>
> Date: Thursday, September 21, 2006 6:12 pm
> Subject: [Jprogramming] UpdateWhere conjunction
>
> > What would be a good definition for the following
> > conjunction, or a better way to achieve the same?
> >
> > UpdateWhere=: 2 : 'if. u y do. v y else. y end.'
> >
> > is there a tacit definition?
>...
J.E.H.Shaw [Ewart Shaw] [EMAIL PROTECTED] TEL: +44 2476 523069
Department of Statistics, University of Warwick, Coventry CV4 7AL, UK
http://www.warwick.ac.uk/statsdept http://www.ewartshaw.co.uk
3 ((4&({*.(=+/))++/=3:)@([:,/0&,^:(i.3)@|:"2^:2))&.>@]^:([EMAIL PROTECTED])
<#:3 6 2
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