Dyalog Forums

Posted: **Sun Mar 28, 2021 4:38 pm**

If that @ wasn't so slow...

      ⍝
 rot_wm4←{⍺←2 ⋄ ⍺>≢⍵:⊂⍵ ⋄ ↓n r⍴(∊(-⍺),/⍵)@(,((1+r)×¯1+⍳n)∘.+⍳⍺)⊢(r×n←1-⍺-r←≢⍵)⍴⍵}
 ]runtime -c "5 rot_wm4 333⍴⎕A" "5 rot_mk2 333⍴⎕A" 
                                                                            
  5 rot_wm4 333⍴⎕A → 8.6E¯5 |   0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕ 
  5 rot_mk2 333⍴⎕A → 6.3E¯5 | -27% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕

But nevertheless, mission accomplished: seemingly there wasn't any new ingenious way to solve the initial problem (which was part of the module for finding typos in a very long list of cd tracks).

-wm

Posted: **Sun Mar 28, 2021 5:49 pm**

Quick and dirty, partly due to passing a noun as ⍺⍺:

rot←{⍺←3 ⋄ ⍺{t←⍵ ⋄ (⍺⍺↑⍺⌽t)←⌽⍺⍺↑⍺⌽t ⋄ t}∘⍵¨¯1+⍳(1-⍺)+≢⍵}

Having to use a temporary for the selective assignment does itch a bit, but it works.

Posted: **Mon Mar 29, 2021 5:41 pm**

Morten|Dyalog wrote:"Flat" APL rocks!

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Is there a better/nicer way?

Re: Is there a better/nicer way?

Re: Is there a better/nicer way?

Re: Is there a better/nicer way?