tolower is not the fastest you can get. Hui gave in
http://www.jsoftware.com/pipermail/programming/2007-July/007302.html
rpl3a=: 4 : 0
'x0 x1'=. x
((x1,a.) {~ (x0,a.) i. ]) y
)
5 ts 'tolower y'[y=.a.{~1e6 [EMAIL PROTECTED] 256
0.024976126 8523008
5 ts ' (((65,.97)+"0 _ i.26){a.)rpl3a y'
0.0051314348 1054400
almost 40 times more efficiënt.
(tolower y) -:(((65,.97)+"0 _ i.26){a.)rpl3a y
1
R.E. Boss
> -----Oorspronkelijk bericht-----
> Van: [EMAIL PROTECTED] [mailto:programming-
> [EMAIL PROTECTED] Namens Sherlock, Ric
> Verzonden: vrijdag 12 oktober 2007 14:23
> Aan: Programming forum
> Onderwerp: RE: [Jprogramming] Performance of case-insensitive lookup
>
> ---Sherlock, Ric wrote
> > --bill lam wrote:
> > > Sherlock, Ric wrote:
> > > > My solutions as follows:
> > > > textend=: {:@$&.>@[ {."1&.> ]
> > > > pplinv textend pinv
> > > > +-------+------+
> > > > |Joan |Saxon |
> > > > +-------+------+
> > > >
> > > > pplinv tindexof pplinv textend pinv
> > > > 4
> > > >
> > >
> > > A potential gotcha is that text in pinv is longer than pplinv, your
> > > solution will trim pinv to shorter length but there should
> > not be any
> > > match because pinv is longer than pplinv. Of course if it is known
> > > before hand that pinv must be shorter than pplinv, there will be no
> > > problem.
> >
> > Very true!
>
> I think this solves that problem:
> tindexof2=: ([,&.>]) tindexof {:@$&.>@([,&.>]) {."1&.>]
>
> p3=: 'Josephine';'Saxon'
> p3inv=: ifa mfv p3
>
> Basically I append the names to be looked up to the lookup table and
> then extend the names to be looked up by the widths of the appended
> lookup table. The lookup is done on the appended table.
> ppl i. p3
> 500
> pplinv tindexof2 p3inv
> 500
>
> Of course if there are more than 1 names to be looked up, the result may
> include indices greater than #ppl, but will still provide the correct
> answer to the normal "is found" test i.e. the resulting index is not
> less than #ppl
> (#ppl)> ppl i. p,p3
> 1 0
> (ttally pplinv)> pplinv tindexof2 pinv ,each p3inv
> 1 0
>
> Performance is only a bit worse:
> ts '(tolower each pplinv) tindexof1 (tolower each p2inv)'
> 0.000125434936563 8320
> ts '(tolower each pplinv) tindexof2 (tolower each p2inv)'
> 0.000133257159779 8320
>
> The phrase [,&.>] is used twice so I wonder if it is possible to
> simplify tindexof2 further?
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