- swapping a matrix

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Anusha
Anusha on 23 Apr 2014
Commented: Geoff Hayes on 24 Apr 2014
a =
1 3 5 6 7
2 3 2 3 2
5 6 7 8 7
b=
5 2 1 3 7
6 8 2 3 1
5 7 8 6 3
how to swap b to a.
ans=
1 3 5 6 7
2 3 2 3 2
5 6 7 8 7

Accepted Answer

Andrew Newell
Andrew Newell on 24 Apr 2014
If I understand your latest comment, you begin by finding the unique numbers:
an = unique(a,'stable').'
bn = unique(b,'stable').'
an =
1 3 5 6 7 2 8
bn =
5 2 1 3 7 6 8
Now you take all the 5's in b and replace them by 1's, all the 2's by 3's, and so on, all at once (otherwise in a later step all the 1's will be changed back to 5's). You can do this by initializing a new matrix and putting all the numbers in it:
c = zeros(size(b));
for i=1:length(an)
idx = (b==bn(i));
c(idx) = an(i);
end
c
c =
1 5 7 8 6
2 3 5 8 7
1 6 3 2 8
This seems to be what you're saying, although the result is completely different from the answer you provided.

More Answers (1)

Andrew Newell
Andrew Newell on 23 Apr 2014
I have two theories for what you mean:
b=a
just makes b equal to a. Or
z=b
b=a
a=z
exchanges the two matrices. I think you need to look at a Matlab tutorial or two.
  8 Comments
Anusha
Anusha on 24 Apr 2014
I use following comments to take a valu an=unique(a,'stable'); bn=unique(b,'stable');
Now swap an and bn in b value. this is useful to get a?
Geoff Hayes
Geoff Hayes on 24 Apr 2014
Was there some sort of suggestion (or part of the problem description) that to do the swap you can use the unique values of a and b (retrieved via stable)?

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