# Find positions where two matrices differ

I have two matrices A and B of identical dimensions. What's the simplest (shortest) way to find the indices of differing elements?

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related: 43938 –  Kuba May 8 '14 at 17:49

SparseArray[A - B]["NonzeroPositions"]

I hope those are numeric matrices, if not then you have to watch out on the Condition in second solution.