Linda,
Your question "Is there a general preference among programmers for count3
or count4" lead me to some experimentation, but I don't think I can answer
your question directly. My preference is for the a composition of smaller
parts, which led to the following sequence which produced, especially in
your preferred linear representation to a surprising result where the
beginning is "-- @ -". I have never noticed such a beginning of a linear
representation, but lr is not my favorite representation, so I rarely use
it.
countB =: <@cb"1@pairs
countBf =: <@cb"1@pairs f.
9!:3 ]5 4
countB
<@cb"1@pairs
┌─ <
┌─ @ ─┴─ cb
┌─ " ───┴─ 1
── @ ─┴─ pairs
countBf
<@([: <"0 >:@i.)"1@(([: >:@i. [) ,"0/ [: >:@i. ])
┌─ <
│ ┌─ [:
┌─ @ ─┤ │ ┌─ <
│ │ ├─ " ─┴─ 0
│ └─────┤
┌─ " ─┤ │ ┌─ >:
│ │ └─ @ ─┴─ i.
│ └─ 1
│ ┌─ [:
│ │ ┌─ >:
── @ ─┤ ┌─────┼─ @ ─┴─ i.
│ │ └─ [
│ │ ┌─ ,
│ ├─ / ─── " ─┴─ 0
└─────┤
│ ┌─ [:
│ │ ┌─ >:
└─────┼─ @ ─┴─ i.
└─ ]
2 (countB -: count) 2
1
On Fri, Feb 13, 2015 at 4:25 AM, Linda Alvord <[email protected]>
wrote:
> Pascal, Your suggestions helped me understand this problem:
>
>
>
> pairs=: 13 :'(>:@i. x),"0/>:@i. y'
>
> cb=: 13 :'<"0 >:@i. y'
>
> cb
>
> [: <"0 >:@i.
>
> count=: 13 :'(<@cb)"1 x pairs y'
>
> 2 count 2
>
> ┌───┬─────┐
> │┌─┐│┌─┬─┐│
> ││1│││1│2││
> │└─┘│└─┴─┘│
> ├───┼─────┤
> │┌─┐│┌─┬─┐│
> ││1│││1│2││
> │├─┤│├─┼─┤│
> ││2│││3│4││
> │└─┘│└─┴─┘│
> └───┴─────┘
>
> --
(B=)
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