Finding column index of the first instance of 1

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I have a logical array like this:
I want to extrat the colum index of the cells where the first instance of 1 is detected. Like this:
For example, you see here that the first two rows show 4, because that is where 1 is first detected.

Accepted Answer

Walter Roberson
Walter Roberson on 2 May 2022
C = sum(cumprod(~X, 2),1) + 1;
C will be one more than the number of columns for any row that has no 1.
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More Answers (1)

Jonas
Jonas on 2 May 2022
use the find() function together with a loop over each row
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Pelajar UM
Pelajar UM on 2 May 2022
Like this?
Doesn't work, because it doesn't find the first instance. It finds all the indices that meet this condition.
for p=1:n %n is the length of the logical array X
G(p,:)=find (X(p,:));
end

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