Some hints to create a tacit verb:
a=.' now is the time for all good men to come to the aidof their country
'
(0<-.' ' E.a)#a
nowisthetimeforallgoodmentocometotheaidoftheircountry
See if you can write a simple expression that gives the result you want.
Then if it is monadic, simply begin name=: 13 : and enter the expression
with y for the argument. Inside a set of single quotes, you must use double
quotes.
fun2=: 13 :'(0<-.'' ''E.y)#y'
fun2
] #~ 0 < [: -. ' ' E. ]
The display of the tacit expression will have been created for you.
fun2 a
nowisthetimeforallgoodmentocometotheaidoftheircountry
And it should work in the same way that your sample worked.
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of [email protected]
Sent: Wednesday, January 04, 2012 9:08 PM
To: Programming forum
Subject: Re: [Jprogramming] Faster deb
How about using E. ?
fun=:verb define
s=.0< -. ' 'E.y
s#y
)
a=.' now is the time for all good men to come to the aid of their country '
fun a
nowisthetimeforallgoodmentocometotheaidoftheircountry
the result is not boxed but leading and trailing blanks are removed.
The timing is, on my now obsolete machine (Athlon 64 5600+ (brisbane 65nm)
and 200Mhz bus)
1000(6!:2)'fun a'
8.91696e_6
I am a novice so I am having problems putting fun into a tacit form- lots of
trial and error.
Essentially, I am taking an APL approach to the problem.
Don Kelly
cross out to reply
-----Original Message-----
From: Marshall Lochbaum
Sent: Wednesday, January 04, 2012 9:41 AM
To: Programming forum
Subject: Re: [Jprogramming] Faster deb
If you really want top-of-the-line performance, you'll have to go to a
sequential machine. Here's my solution, which leaves the leading and
trailing blanks in, then specifically deletes them.
I don't claim that these tests are universal; it's quite plausible that a
different mixture of blanks and words would give different results.
Of course, benefits are marginal, and if performance is REALLY critical, I
would advise just wasting the 20 lines and 10 minutes that it takes to code
the thing in C.
ws =. ' ',TAB,LF
dlb =. }.^:(ws e.~{.) NB. delete leading blank
dtb =. }:^:(ws e.~{:) NB. delete trailing blank
m =. ws -.@:e.~ a.
s =. 2 2 2$ 0 1 1 2 0 2 1 0
sdeb =: [: dlb@:dtb (1;s;m)&;:
fdeb =: [: dlb [ #~ [: -. [: (] *. 1&|.) ' ' = [
test =. ; ' test'&,&.> (1e5?@$10) <@$"0 ]' '
100 (6!:2) 'deb test'
0.0167294
100 (6!:2) 'sdeb test'
0.012571
100 (6!:2) 'fdeb test'
0.0162943
(deb -: sdeb) test
1
(deb -: fdeb) test
1
Marshall
On Wed, Jan 4, 2012 at 11:53 AM, Ian Clark <[email protected]> wrote:
> okay, I didn't read Raul's posting properly.
>
> On Wed, Jan 4, 2012 at 4:44 PM, Ian Clark <[email protected]> wrote:
> > Raul's points are valid, but as a technique I like it. I'm going to
> > add it to my collection of idioms for a monograph on string-handling.
> >
> > Rotate-and-compare can be generalized to detect any given letter
> > followed/preceded by some other. But in the speed stakes, there's
> > often extra housekeeping handling the string ends.
> >
> > Harking back to a recent thread where (;:inv) came up, how about these
> too?
> >
> > wdeb=: ;:inv @ ;:
> > udeb=: ] &. ;: NB. a faster variant of the same idea
> >
> > Not as fast as either deb or fdeb, (besides mishandling punctuation)
> > but with a certain idiot appeal. And try replacing (]) with (|.),
> > (~.), sort, etc.
> >
> > In my monograph, (;:) will have a chapter to itself.
> >
> >
> > On Wed, Jan 4, 2012 at 1:54 PM, Raul Miller <[email protected]>
> wrote:
> >> As you point out, these are not equivalent.
> >>
> >> # TEST=: ' this is a test '
> >> 26
> >> # deb TEST
> >> 14
> >> # fdeb TEST
> >> 15
> >>
> >> Note also:
> >> # ]&.;: TEST
> >> 14
> >>
> >> That said:
> >> # ]&.;: ' Don''t do this... '
> >> |open quote
> >>
> >> Also, the timing difference between 3.446e_6 and 3.293e_6 is
> inconsequential.
> >>
> >> --
> >> Raul
> >>
> >> On Wed, Jan 4, 2012 at 2:14 AM, Alan Stebbens <[email protected]> wrote:
> >>> "delete extra blanks" from strings.ijs has this definition:
> >>>
> >>> deb =: #~ (+. (1: |. (> </\)))@(' '&~:)
> >>>
> >>> NB. Here is a slightly faster deb:
> >>>
> >>> fdeb =: [ #~ [: -. [: (] *. 1&|.) ' ' = [
> >>>
> >>> NB. s is the test string; w is its boxed words
> >>>
> >>> w=.;:s=.'now is the time for all good men to come to the aid of
> their country'
> >>> w
> >>> +---+--+---+----+---+---+----+---+--+----+--+---+---+--+-----+-------+
> >>> |now|is|the|time|for|all|good|men|to|come|to|the|aid|of|their|country|
> >>> +---+--+---+----+---+---+----+---+--+----+--+---+---+--+-----+-------+
> >>>
> >>> NB. show
> >>> 1000 tx 'deb ,>w'
> >>> 3.446e_6 3072
> >>>
> >>> 1000 tx 'fdeb ,>w'
> >>> 3.293e_6 3072
> >>>
> >>> NB. same value for both the old and new fun
> >>> (deb -: fdeb),>w
> >>> 1
> >>>
> >>> NB. the results match the original string
> >>> s -: fdeb ,>w
> >>> 1
> >>>
> >>> However, it's not exactly the same as deb: it doesn't remove a single
> leading blank, as does deb (which, IMHO, is not necessarily an "extra"
> blank anyway).
> >>>
> >>> Alan
> >>>
> >>>
> >>>
> >>> ----------------------------------------------------------------------
> >>> For information about J forums see http://www.jsoftware.com/forums.htm
> >> ----------------------------------------------------------------------
> >> For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
