Since
;: b._1
}:@;@(,&' '&.>"1) :.;:
and (' '&joinstring) compared to (;:^:_1) is not only 20% faster but is
also 4 times as lean, (;:b._1) better can be
redefined.
R.E. Boss
> -----Oorspronkelijk bericht-----
> Van: [email protected]
> [mailto:[email protected]] Namens Ric Sherlock
> Verzonden: vrijdag 7 september 2012 9:18
> Aan: [email protected]
> Onderwerp: Re: [Jprogramming] flattening boxed strings
>
> None of these versions seem to provide much (any?) benefit over and
> above the joinstring verb from strings.
>
> timespacex 'b2o x'
> 0.145468 4.1748e7
> timespacex 'b2q x'
> 0.145305 4.1748e7
> timespacex 'SP joinstring x'
> 0.143562 4.17485e7
>
> When we inspect joinstring the reason becomes clear ... they are doing
> essentially the same thing except that joinstring takes a left
> argument which defaults to ''.
> joinstring=: ''&$: : (#@[ }. <@[ ;@,. ])
> bto=: }.@((<' ') ;@,. ])
>
> Note that the inverse of joinstring is:
> splitstring=: #@[ }.each [ (E. <;.1 ]) ,
>
>
> On Fri, Sep 7, 2012 at 5:00 PM, Roger Hui <[email protected]> wrote:
> > SP=: ' '
> > b2o=: }.@((<SP) ;@,. ])
> > b2q=: }:@((<SP) ;@,.~ ])
> >
> > x=: (1e6 ?@$ 20) $&.> 'x'
> >
> > (b2o -: b2q) x
> > 1
> >
> > timer 'b2o x'
> > 0.388007
> > timer 'b2q x'
> > 0.262082
> >
> >
> >
> > On Thu, Sep 6, 2012 at 4:07 PM, Ian Clark <[email protected]> wrote:
> >
> >> Quite right, Raul. And strings containing newlines do matter to me. A lot.
> >>
> >> I confess I only threw in bpv as a bit of a joke. It relies on 5!:5
> >> converting boxed z to...
> >> <;._1 ' alpha bravo charlie'
> >> which it doesn't always. In fact, it returns your example without change
> >> ...
> >>
> >> z123=: '1';'2';'3'
> >> 5!:5 <'z123'
> >> '1';'2';'3'
> >>
> >> So I fear bpv doesn't merit close attention.
> >>
> >> (I suspect ;:inv will eventually let me down too, but I haven't fooled it
> >> yet!)
> >>
> >> b2o and its sister b2f do matter, however, as I propose to put serious
> >> weight on them, as g.p. utilities.
> >>
> >> b2o=: }.@((<SP) ;@,. ])
> >> b2f=: }.@((<LF) ;@,. ])
> >>
> >> so I'd be grateful to be notified of anyone making them misbehave.
> >>
> >> Possible gray areas to investigate: use of i{a. where i>127, utf-8,
> >> boxed scalars, strings with CRLF, 0{a. and other subasciis, uses of a:
> >> , etc, etc.
> >>
> >> On Thu, Sep 6, 2012 at 11:43 PM, Raul Miller <[email protected]>
> >> wrote:
> >> > Note that bpv would also have problems with boxed strings containing
> >> > spaces, and even worse problems with boxed strings containing
> >> > newlines. (It's not clear, though, if strings containing newlines
> >> > matter to you.)
> >> >
> >> > --
> >> > Raul
> >> >
> >> > On Thu, Sep 6, 2012 at 6:39 PM, Ian Clark <[email protected]> wrote:
> >> >> Right you are.
> >> >>
> >> >> What I really want (but haven't said) is the fastest versions of b2o
> >> >> (boxed-to-open-string) and b2f (boxed-to-LF-separated-string), where
> >> >> b2f is b2o with ' ' (-:SP) replaced with LF.
> >> >>
> >> >> I think I've got them now, thanks to everyone.
> >> >>
> >> >> BTW solutions involving deb aren't general enough, esp for b2f, where
> >> >> the boxed strings may validly contain multiple spaces.
> >> >>
> >> >> On Thu, Sep 6, 2012 at 11:32 PM, Raul Miller <[email protected]>
> >> wrote:
> >> >>> I prefer
> >> >>> ;:inv z
> >> >>>
> >> >>> But note that
> >> >>>
> >> >>> deb,' ',.>z
> >> >>>
> >> >>> would work. (J6 users need require'strings' before this can work.)
> >> >>>
> >> >>> FYI,
> >> >>>
> >> >>> --
> >> >>> Raul
> >> >>>
> >> >>> On Thu, Sep 6, 2012 at 6:21 PM, Ian Clark <[email protected]>
> >> wrote:
> >> >>>> Yes, but we need a string.
> >> >>>> You can ravel the 2D array to get a string, viz:
> >> >>>> ,> z
> >> >>>> but it gives you a varying number (0 or more) of separating spaces.
> >> >>>>
> >> >>>> On Thu, Sep 6, 2012 at 10:50 PM, km <[email protected]> wrote:
> >> >>>>> > 'alpha';'bravo';'charlie'
> >> >>>>> alpha
> >> >>>>> bravo
> >> >>>>> charlie
> >> >>>>>
> >> >>>>> I'm resending because the echo from Jsoftware to my iPad was
> >> incorrect. Hope this one shows my solution was to open the list of boxes.
> >> >>>>>
> >> >>>>> Sent from my iPad
> >> >>>>>
> >> >>>>>
> >> >>>>> On Sep 6, 2012, at 4:32 PM, km <[email protected]> wrote:
> >> >>>>>
> >> >>>>>>> 'alpha';'bravo';'charlie'
> >> >>>>>> alpha
> >> >>>>>> bravo
> >> >>>>>> charlie
> >> >>>>>>
> >> >>>>>> (shape 3 7)
> >> >>>>>>
> >> >>>>>> Sent from my iPad
> >> >>>>>>
> >> >>>>>>
> >> >>>>>> On Sep 6, 2012, at 11:38 AM, Ian Clark <[email protected]>
> >> wrote:
> >> >>>>>>
> >> >>>>>>> Kindergarten class...
> >> >>>>>>>
> >> >>>>>>> I have a list of boxed literals...
> >> >>>>>>> z=: 'alpha' ; 'bravo' ; 'charlie'
> >> >>>>>>>
> >> >>>>>>> I want to flatten it to a literal, but with spaces between.
> >> (Variant:
> >> >>>>>>> --with LF's).
> >> >>>>>>>
> >> >>>>>>> Raze (;) does indeed flatten the list...
> >> >>>>>>> ;z
> >> >>>>>>> alphabravocharlie
> >> >>>>>>>
> >> >>>>>>> There's got to be a really neat extended Raze which includes
> >> >>>>>>> separators. But the fastest I've been able to come up with is:
> >> >>>>>>>
> >> >>>>>>> b2o=: }.@((<' ') ;@,. ])
> >> >>>>>>> b2o z
> >> >>>>>>> alpha bravo charlie
> >> >>>>>>>
> >> >>>>>>> Any advances?
> >> >>>>>>>
> >> ----------------------------------------------------------------------
> >> >>>>>>> For information about J forums see
> >> http://www.jsoftware.com/forums.htm
> >> >>>>>>
> >> ----------------------------------------------------------------------
> >> >>>>>> For information about J forums see
> >> http://www.jsoftware.com/forums.htm
> >> >>>>>
> >> ----------------------------------------------------------------------
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> >> http://www.jsoftware.com/forums.htm
> >> >>>> ----------------------------------------------------------------------
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> >> http://www.jsoftware.com/forums.htm
> >> >>> ----------------------------------------------------------------------
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> >> >> ----------------------------------------------------------------------
> >> >> For information about J forums see http://www.jsoftware.com/forums.htm
> >> > ----------------------------------------------------------------------
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> >> ----------------------------------------------------------------------
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> >>
> > ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
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