Finding the indexes of first zero value in rows of a matrix?

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Hi all, I have a matrix full of zero and one. However, I just want to have a vector including the index (Column number) of the first zero in each row. Any suggestion and help really appreciated.

Accepted Answer

Walter Roberson
Walter Roberson on 28 Nov 2017
index_first_row_zero = sum( cumprod(logical(YourMatrix), 2), 2) + 1;
Note: in the case where none of the entries are 0, this returns one more than the width. You did not define the desired output for this case.
index_last_nonzero = size(YourMatrix,2) - sum( cumprod( ~logical(YourMatrix), 2, 'reverse'), 2);
Note: in the case where all of the entries are 0, this returns 0. You did not define the desired output for this case.

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