sorting according to another vector
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Danielle Leblanc
on 5 Aug 2011
Commented: Walter Roberson
on 10 Feb 2022
Hi,
I have a vector A that doesn't follow any order. I want to sort Matrix B that has the first column of values similar to those of A but in different order. Is it possible to sort B according to A using a single function or should I write many codes to do so?
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Accepted Answer
Walter Roberson
on 5 Aug 2011
Sorry you will have to use multiple calls:
[a_sorted, a_order] = sort(A);
newB = B(a_order,:);
1 Comment
Jan
on 5 Aug 2011
@Danielle: Ok, then I have misunderstood your question. The information that B has "value similar to those of A" is meaningless then - correct?
More Answers (4)
Jan
on 5 Aug 2011
I'm not sure, if I understand the question correctly. Do you want to bring B in the same order as the unsorted A? Then either sort both vectors and mix their sorting indicies:
[As, Ai] = sort(A);
[Bs, Bi] = sort(B(:, 1));
ABi(Ai) = Bi;
Now ABi is the sorting index to bring B to the order of A:
isequal(A, B(ABi, 1)) % ==> 1
Or let ISMEMBER do this for you:
[dummy, order] = ismember(A, B(:, 1));
isequal(A, B(order, 1)) % ==> 1
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Pramit Biswas
on 31 Jan 2018
Edited: Pramit Biswas
on 31 Jan 2018
function B = sortBlikeA(A,B)
[~, Ao] = sort(A);
Bs=sort(B);
B(Ao)=Bs;
end
inzamam shoukat
on 26 Oct 2018
Edited: inzamam shoukat
on 26 Oct 2018
Hi every one......i have matrix lets suppose [3 2;1 9]
what i want to do is sort out the only first column in ascending order but problem is how to do it so that corresponding values which is in first row 2 for 3 in second row 9 for 1 change their positions according to the position of values of first column being sorted i.e [1 9; 3 2]...
LIMITATION : sorting operation never applied to second column....
2 Comments
Marco Bertola
on 14 Feb 2021
Edited: Marco Bertola
on 14 Feb 2021
I think the question (which I had too) was:
I have a reference vector [1.2 3.3 4.4] eg
and another ``similar'' vector [3.2 1.1 4.4]
Problem; find the optimal sorting of vector 2 so that it is ''closest'' (L^2 norm eg) to the reference vector.
Say X is your reference vector of size (1,n) and Xnew is the new vector of the same size
then what you want is accomplished like so:
dist = abs(ones(n,1)*X - Xnew.' ones(1,n));
[t1,J]= min(dist);
%now J has the optimal permutation%
Xnew=Xnew[J]
1 Comment
Walter Roberson
on 10 Feb 2022
If you are not permitted to duplicate any elements, and the entries are all finite then
[~, refidx] = sort(reference_vector);
sorted_similar = sort(similar_vector);
new_similar = sorted_similar(refidx);
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