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How to "partner" 2 matrixes

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Hugo Matias
Hugo Matias on 30 Nov 2018
Commented: Guillaume on 2 Dec 2018
The matrix X is randomly shuffled, how does Y follow up that shuffle?
i.e:
X=[4 7 1 9;
3 0 6 8]
Y=[32 6 4 21;
77 89 0 2]
after the shuffle:
X=[3 9 4 6;
1 7 8 0]
Y=[77 21 32 0;
4 6 2 89]

Accepted Answer

Guillaume
Guillaume on 30 Nov 2018
X = [4 7 1 9;
3 0 6 8]
Y = [32 6 4 21;
77 89 0 2]
newX = [3 9 4 6;
1 7 8 0]
[found, where] = ismember(newX, X);
assert(all(found(:)), 'some elements of newX are not present in X')
newY = Y(where)
  3 Comments
Hugo Matias
Hugo Matias on 1 Dec 2018
Edited: Guillaume on 2 Dec 2018
Hi, how do I do the same thing but instead of that this:
(imagine "a" as a number)
How do I do this?
X=[4 7 1 0;
3 0 6 8]
Y=[32 6 4 21;
77 89 0 2]
X(X==0)=a;
after the alteration:
X=[4 7 1 a;
3 a 6 8]
Y=[ 32 6 4 a;
77 a 0 2];
Guillaume
Guillaume on 2 Dec 2018
Keep the list of elements you're going to replace (i.e. the logical array X == 0) so that you can use for Y as well:
X=[4 7 1 0;
3 0 6 8]
Y=[32 6 4 21;
77 89 0 2]
toreplace = X == 0;
X(toreplace) = a;
Y(toreplace) = a;

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More Answers (1)

madhan ravi
madhan ravi on 30 Nov 2018
Edited: madhan ravi on 30 Nov 2018
X=[4 7 1 9;
3 0 6 8]
idx=randsample(1:numel(X),numel(X));
shuffled_X=reshape(X(idx),size(X,1),[])
Y=[32 6 4 21;
77 89 0 2]
shuffled_Y=reshape(Y(idx),size(Y,1),[])
command window:
>> COMMUNITY
X =
4 7 1 9
3 0 6 8
shuffled_X =
1 0 3 7
8 9 4 6
Y =
32 6 4 21
77 89 0 2
shuffled_Y =
4 89 77 6
2 21 32 0
>>
  1 Comment
Hugo Matias
Hugo Matias on 30 Nov 2018
I didn't mean shuffled like that, sorry!
I mean I change the numbers positions of the matrix X
and matrix Y will replicate the movements

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