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fix at +2, and add explanation

edited Aug 3, 2021 at 9:41

APL (Dyalog Unicode), 1012 bytes

Anonymous tacit prefix function.

⊂(∨/¨⍳∊¨1=,¨⊂1∊⊢)¨⍳

⊂(…)¨⍳ apply the following tacit infix function between the entire argument and each index in an array of those dimensions:

1∊⊢ is there a 1 in the index?

=, prepend a Boolean list indicating which coordinate are equal to the corresponding element of the original argument

∨/ are any true? (lit. OR reduction)

∨/¨⍳∊¨1,¨⊂

Anonymous tacit prefix function.

⊂(∨/=,1∊⊢)¨⍳

⊂(…)¨⍳ apply the following tacit infix function between the entire argument and each index in an array of those dimensions:

1∊⊢ is there a 1 in the index?

=, prepend a Boolean list indicating which coordinate are equal to the corresponding element of the original argument

∨/ are any true? (lit. OR reduction)

answered Aug 3, 2021 at 9:09

∨/¨⍳∊¨1,¨⊂