I have a matrix BB = [-1 5 6;4 -3 2;5 6 -7]. How can i print the location(index) of the positive elelments using for loop and using while loop ?

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Fares Alfares 2018-7-24

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https://ww2.mathworks.cn/matlabcentral/answers/411966-i-have-a-matrix-bb-1-5-6-4-3-2-5-6-7-how-can-i-print-the-location-index-of-the-positive-ele

评论： Fares Alfares 2018-7-25

I have this matrix BB = [-1 5 6;4 -3 2;5 6 -7]. I want to know how can I display the location of the positive elements using for loop and using while loop

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Paolo 2018-7-24

That's not the correct syntax for a for loop. Check this documentation page: link

Fares Alfares 2018-7-24

在 MATLAB Online 中打开

I tried to do this i=[1:length(BB)] for BB = [-1 5 6;4 -3 2;5 6 -7] if (BB(i) >= 0) i end end it gave me :i =

     1     2     3
and I tried to do 
BB = [-1 5 6;4 -3 2; 5 6 -7]
i = [1:length(BB)]
for (BB(i)>= 0)
i
end
it gave me :BB =
    -1     5     6
     4    -3     2
     5     6    -7

i =

     1     2     3
 for (BB(i)>= 0)
        ↑
Error: Invalid expression. When calling a function or
indexing a variable, use parentheses. Otherwise, check for
mismatched delimiters.

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采纳的回答

KSSV 2018-7-25

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https://ww2.mathworks.cn/matlabcentral/answers/411966-i-have-a-matrix-bb-1-5-6-4-3-2-5-6-7-how-can-i-print-the-location-index-of-the-positive-ele#answer_330214

在 MATLAB Online 中打开

BB = [-1 5 6;4 -3 2;5 6 -7] ;
[nx,ny] = size(BB) ;
for i = 1:nx
    for j = 1:ny
        if BB(i,j)>0
            fprintf('%d %d %f\n',i,j,BB(i,j))
        end
    end
end