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Challenges

Comments on Truthify an array

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Truthify an array

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Jelly has an atom called untruth, which when given indices, creates an array with 1s at those places: [2,4] → [0,1,0,1].

You are required to perform the inverse of this. Given a 2D boolean array, find the indices of the true values in it.

Challenge

You will be given a single 2D boolean array $M$. You may take its dimensions as a separate argument if needed.

The output must consist of all the indices of the true values in $M$.

Output may be 0-indexed or 1-indexed.

It is guaranteed that the input will only consist of two different values.

Test Cases

All test cases are 0-indexed.

I: [[1,0,1,1,1,0]]
O: [[0,0],[0,2],[0,3],[0,4]]

I: [[1,0,1],[1,0,1],[0,1,0]]
O: [[0,0],[0,2],[1,0],[1,2],[2,1]]

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APL (Dyalog Extended), 1 byte

¯\(ツ)

Try it online!

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General comments
Razetime‭ wrote about 3 years ago

I was waiting for this one..