[Jprogramming] @ and @: (atop and at)

[Raul Miller]

Order is important.

Do you see why?

(Hint: it has to do with implicit parenthesis provided by parsing.)

Thanks,

-- 
Raul


On Fri, Jan 22, 2016 at 10:55 AM, Brian Schott <schott.brian at gmail.com> wrote:
> [Sorry, that was a mistake. This is a resend]
>
>    #@:>@:;:'a man a plan a canal'     NB. 1
> 6
>    #@:>@;:'a man a plan a canal'     NB. 2
> 6
>    #@>@;:'a man a plan a canal'     NB. 3
> 1 3 1 4 1 5
>    #@>@:;:'a man a plan a canal'     NB. 4
> 1 3 1 4 1 5
>    #@(>@:;:)'a man a plan a canal'     NB. 5
> 6
>    #@(>@;:)'a man a plan a canal'     NB. 6
> 6
>
> These examples are hard for me to grok.
> Comparing 1 and 2 and 4 suggests that either order is important or that #
> is effected and > is not.
> Example 6 suggests that parentheses can produce results like @: especially
> when compared with 2.
>
> My experience in the past has been especially puzzling when I try to
> combine atop with the MIDDLE TINE result of a fork as the following
> examples attempt to cover. In these example I use at and atop in the names
> to reflect the use of @ and @: ; I use app in the names to reflect the use
> of append . These examples especially the comparison between the
> application of meanatop and meanatopapp, clarify to me that atop uses the
> rank of its predecessor (%
>
>    mean i. 3 4
> 4 5 6 7
>    meanat =: +/ #@% #
>    meanat i. 3 4
> 1 1 1 1
>    meanatop =: +/ #@:% #
>    meanatop i. 3 4
> 4
>    meanatapp =: +/ #@,@% #
>    meanatapp i. 3 4
> 1 1 1 1
>    meanatopapp =: +/ #@:,@% #
>    meanatopapp i. 3 4
> 1 1 1 1
>    meanatopappparen =: +/ #@(,@%) #
>    meanatopappparen i. 3 4
> 1 1 1 1
>    meanatappparen =: +/ #@:(,@%) #
>    meanatappparen i. 3 4
> 4
>
>
> On Fri, Jan 22, 2016 at 4:50 AM, Linda A Alvord <lindaalvord at verizon.net>
> wrote:
> I think I finally understand the difference!
>
>     A=:'a man a plan a canal'
>    ;:A
> ┌─┬───┬─┬────┬─┬─────┐
> │a│man│a│plan│a│canal│
> └─┴───┴─┴────┴─┴─────┘
>    f=: 13 :'#>;:y'
>    g=: 13 :'#@>;:y'
>    h=: 13 :'#@:>;:y'
>
>
> --
> (B=) <-----my sig
> Brian Schott
> ----------------------------------------------------------------------
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