A compact way to replace zeros with Inf in a matrix
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Would you be so nice to suggest me a more compact way to replace zeros with Inf in the following matrix? (maybe with just one line of code?)
% Input
A = [0 3 2 5 6;
1 1 4 3 2;
9 0 8 1 1;
5 9 8 2 0;
3 1 7 6 9];
% Replace zeros with Inf
[row,col] = ind2sub(size(A),find(A==0));
for i = 1 : length(row)
A(row(i),col(i))=Inf;
end
% Output
A
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采纳的回答
J. Alex Lee
2023-10-16
编辑:J. Alex Lee
2023-10-16
You can implicitly index "linearly" for any arrays - it will do all the ind2sub and sub2ind in the background:
% Input
A = [0 3 2 5 6;
1 1 4 3 2;
9 0 8 1 1;
5 9 8 2 0;
3 1 7 6 9];
B = A;
% Replace zeros with Inf
[row,col] = ind2sub(size(A),find(A==0));
for i = 1 : 3
A(row(i),col(i))=Inf;
end
% Output
A
B(B==0) = Inf
isequal(A,B)
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更多回答(4 个)
Les Beckham
2023-10-16
编辑:Les Beckham
2023-10-16
If you want to retain the non-zero elements of A and replace the zeros with Inf, then this is how I would suggest that you do that.
% Input
A = [0 3 2 5 6;
1 1 4 3 2;
9 0 8 1 1;
5 9 8 2 0;
3 1 7 6 9];
A(A==0) = Inf
Note that your loop doesn't do this, it creates a matrix with Inf in the positions of the zeros in A and zero everywhere else. If that is really what you want then you could do that like this.
A = [0 3 2 5 6;
1 1 4 3 2;
9 0 8 1 1;
5 9 8 2 0;
3 1 7 6 9];
B = zeros(size(A));
B(A==0) = Inf
3 个评论
Les Beckham
2023-10-16
编辑:Les Beckham
2023-10-16
You are quite welcome.
If you are just getting started with Matlab, I would highly recommend that you take a couple of hours to go through the free online tutorial: Matlab Onramp
Matt J
2023-10-16
Allso just for fun.
A = [0 3 2 5 6;
1 1 4 3 2;
9 0 8 1 1;
5 9 8 2 0;
3 1 7 6 9];
A=A+1./(A~=0)-1
Walter Roberson
2023-10-23
A = [0 3 2 5 6;
1 1 4 3 2;
9 0 8 1 1;
5 9 8 2 0;
3 1 7 6 9];
A(~A) = inf
2 个评论
Alexander
2023-10-16
Only for fun. My maybe a bit old-fashoned approach would be:
B=1./A;
B(B==Inf)=0;
C=1./B
6 个评论
Stephen23
2023-10-23
"But I think it depends on the problem you have to solve whether these are significant or not."
I can't think of many problems where a more complex, slower, obfuscated approach with precision errors would be preferred over the simpler, clearer, much more robust approach using indexing. Can you give an example?
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