]x=. 0 4 5 e.~ i.3 3
1 0 0
0 1 1
0 0 0
I.x
0 0
1 2
0 0
I am genuinely curious: is the latter result of use to anyone?
Why not this instead?
where=. , # $ #: i.@#@,
where x
0 0
1 1
1 2
-E
P.S. current scheme throws away information senselessly.
]y=. 3 3 $ 2 0 0 0 1 1 0 0 0
2 0 0
0 1 1
0 0 0
x (-: , -:&:I.) y
0 1
P.P.S. proposed definition is effectively Dyalog's 'where', but without
nesting.
⊢x← 0 4 5 ∊⍨ 3 3⍴⍳9
1 0 0
0 1 1
0 0 0
⍸x
0 0 1 1 1 2
P.P.P.S. a truly horrifying fact that was pointed out to me on lobsters (a
webforum): if you only care about the boolean case, you may also use:
4&$.@$.
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