okay, I didn't read Raul's posting properly.
On Wed, Jan 4, 2012 at 4:44 PM, Ian Clark <earthspo...@gmail.com> 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 <rauldmil...@gmail.com> 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 <a...@stebbens.org> 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
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