sorry about that... forgot to include the xxs
definition.
xxs =: ({.);(<@:}.)
ListBlock=: 2 : 0
NB. Loops through list passing head u rest to dyad u.
NB. results accumulated to lastreturns v newresult
NB. Purpose: like / but passes full rest of list on
right.
try. last=. (v/ i.0) catch. last=. i.0 end. NB. v
must have an identity function defined
while. 1<#y [ 'h y' =. xxs y do.
last=. last v h u y
end.
last=. last v h u y
)
ListBlocK=: (ListBlock ,)
--- Jose Mario Quintana
<[EMAIL PROTECTED]> wrote:
> > On Behalf Of Pascal Jasmin
> > Sent: Tuesday, September 26, 2006 4:18 PM
> > A few applications,
> >
> > raw list of subsequent duplicates
> > ((-.@:i.)) ListBlock (,<) 1 3 2 4 3 1 1 2
> >
>
+-------------+-----------+---------+-------+-----+---+-+
> > |0 0 0 0 1 1 0|0 0 1 0 0 0|0 0 0 0 1|0 0 0 0|0 0
> 0|1
> > 0|0|
> >
>
+-------------+-----------+---------+-------+-----+---+-+
> >
> > Count of subsequent duplicates (boxed then
> unboxed)
> > > ((+/@:-.@:i.)) ListBlock (,<) 1 3 2 4 3 1 1 2
> > 2 1 1 0 0 1 0
> >
> > Link to next duplicate item.
> > ((i.~)) ListBlocK 1 3 2 4 3 1 1 2
> > 4 2 4 4 3 0 1
>
> I tried to compare the performance of a
> straightforward,
>
> lb=. ({.`) (`}.) (`:6) \. (}:@:)
>
> U lb
> }:@:(({. U }.)\.)
>
> (i.~) lb 1 3 2 4 3 1 1 2
> 4 2 4 4 3 0 1
>
> vs. ListBlocK; but I got,
>
> ((i.~)) ListBlocK 1 3 2 4 3 1 1 2
> |value error: xxs
> | 1<#y['h y'=. xxs y
>
>
>
> >
> > --- Pascal Jasmin <[EMAIL PROTECTED]> wrote:
> >
> > > This control structure is a variation on the /
> > > adverb.
> > > There is both an adverb form, and more general
> > > conjunction form. The adverb u ListBlocK 1 2 3
> 4 is
> > > equivalent to:
> > > (1 u 2 3 4) , (2 u 3 4) , (3 u 4)
> > >
> > > The more general conjunction form (u ListBlock
> v) 1
> > > 2
> > > 3 4 is equivalent to:
> > > (1 u 2 3 4) v (2 u 3 4) v (3 u 4)
> > >
> > > and also equivalent to
> > > v/ (u ListBlocK) 1 2 3 4
> > >
> > > The control structure is more equivalent to
> > > lisp/haskell style which use explicit functions
> that
> > > have the entirety of the tail available as a
> > > parameter
> > > to combine with successive head items. The most
> > > practical operation is relationship testing
> between
> > > members and the rest of the list, in n*n/2 time
> > > instead of n*n.
> > >
> > > ListBlock=: 2 : 0
> > > NB. Loops through list passing head u rest to
> dyad
> > > u.
> > > NB. results accumulated to lastreturns v
> newresult
> > > NB. Purpose: like / but passes full rest of
> list on
> > > right.
> > > try. last=. (v/ i.0) catch. last=. i.0 end.
> NB.
> > > v
> > > must have an identity function defined, or
> otherwise
> > > deal with i.0 v (h u y).
> > > while. 1<#y [ 'h y' =. xxs y do.
> > > last=. last v h u y
> > > end.
> > > last=. last v h u y
> > > )
> > > ListBlocK=: (ListBlock ,)
> > >
> > > f=: 4 : 'x + +/ y'
> > > (f ListBlocK) 1 2 3 4
> > > 10 9 7
> > > (f ListBlock +) 1 2 3 4
> > > 26
> > >
> > > Maybe InsertWhole would be a better name for it?
> > >
> > >
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