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Replace elements between two matrices

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Ismael
Ismael on 6 Dec 2016
Edited: Ismael on 7 Dec 2016
I have two matrices A and B:
A= [8 1;
16 2];
B= [8 10;
16 5]
I want to replace any element in B that exist in the 1st column of A, by its corresponding value in the second column of A. The result should be:
C=[1 10;
2 5];
Thanks for help

Accepted Answer

Image Analyst
Image Analyst on 7 Dec 2016
Try this:
A= [8 1;
16 2]
B= [8 10;
16 5]
% If A & B are integers
rowsToReplace = A(:, 1) == B(:, 1)
C = B; % Initialize C to B.
% Now, replace the rows that need replacing:
C(rowsToReplace, 1) = A(rowsToReplace, 2)
  2 Comments
Ismael
Ismael on 7 Dec 2016
Image Analyst, sorry but how about if size(A)~=size(B)? I have a case in this pattern.

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More Answers (1)

Chaya N
Chaya N on 7 Dec 2016
Try the setxor function. You may need to tweak the directionality of the inputs a bit, so use something like
C = setxor(A',B','rows')'
  3 Comments
Ismael
Ismael on 7 Dec 2016
That is true for the case when the first column in A and B are the same. How about if some elements of the 1st column of B are not similar to the elements in the 1st column of A. If, for instance, the element (1,1) in B which is =8 is any number except 8, I don't want to keep different elements and replace similars with their corresponding second column in A.
Simply,
if B(i,1)==A(i,1)
replace B(i,1) with A(i,2)
otherwise don't change

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