hi, I have array a = [5 4 0;3 1 0;5 7 0], how can I replace the value in third column (a(:,3)) with the values in column 1 (a(:,1)) when a(:,1) > a(:,2) . I need obtain [5 3,5] in the third column

Answer 1

[Image Analyst]

But when col 1 is less than col 2, you're still replacing it. Just look at your third row. Please make your explanation match your example. You just simply replaced column 3 with column 1 regardless of what column 2 is.

Perhaps you mean this:

m = [5,4,0; 3,1,0; 5,7,0]
% Assign column 1 to column 3
% but only when it's greater than column 2
rowsToReplace = m(:, 1) > m(:, 2)
m(rowsToReplace, 3) = m(rowsToReplace, 1)

[julios]

Yes, it was what I need, I was wrong in the explanation, thank you very much

Answer 2

[Gareth Lee]

I think the description of your question is not clear, a(:,1)>a(:,2) is a column vector not all true. Is this your judge condition?

if all(a(:,1)>a(:,2))
   a(:,3)=a(:,1);
end

Is this that your want ?

[julios]

Yes, your approach is correct, I was wrong in my explanation. that is what I need, thanks

[Gareth Lee]

Since my answer is right, please vote it even though you accept another answer.

[julios]

Tanks