swap columns of a matrix

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Rasmus
Rasmus am 25 Feb. 2014
Hello guys/girls
How do i swap columns??
I have this
k_minus =
-46 -43 -26 -14 7 19 11 32 39 45 45
0 -4 -7 -7 -44 -44 -7 -7 -15 -15 0
and I want the columns to be in opposite order - How do I do this? and can do this in one go?
  1 Kommentar
Keerthi Krishna PARVATHANENI
Easy way is to swap the coloums based on the positon
For example:
A=[10 20 30;
40 50 60];
swap the coloum 1 to 2 can be done by
A(:,[2 1 3])
ans =
20 10 30
50 40 60
Exact approach can be adopted ot swap rows
A([2 1],:)
ans =
40 50 60
10 20 30
I think, this can be easy way with minium code.
Enjoy :)

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Akzeptierte Antwort

Thomas
Thomas am 25 Feb. 2014
Bearbeitet: Thomas am 25 Feb. 2014
You could also use
out= fliplr(k_minus)
  1 Kommentar
Rasmus
Rasmus am 25 Feb. 2014
That is actually easier! :)

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Weitere Antworten (2)

Mischa Kim
Mischa Kim am 25 Feb. 2014
Bearbeitet: Mischa Kim am 25 Feb. 2014
Use
k_minus_rev = k_minus(:, [length(k_minus(1,:)):-1:1])
  4 Kommentare
Jos (10584)
Jos (10584) am 25 Feb. 2014
You do not need the length statement by using the keyword END:
MyMatrix_withReversedColumns = MyMatrix(:,end:-1:1)
but I do suggest you stick to FLIPLR. It is the same, but much easier to read!
kk
kk am 2 Apr. 2019
Thank you for this answer! It has helped me "merge" two matrices, i.e. creating a matrix consisting of the first column of matrix A, first column of matrix B, second column of matrix A, second column of matrix B, etc.

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rishabh gupta
rishabh gupta am 12 Jan. 2018
you can also use: k_minus_rev = k_minus(:, [length(k_minus):-1:1])
  2 Kommentare
Stephen23
Stephen23 am 12 Jan. 2018
Bearbeitet: Stephen23 am 12 Jan. 2018
The square brackets are totally superfluous, and using end is simpler than using length (of course length should be avoided generally because its output changes depending on the input array size: better to use numel or size with a specific dimension).
So a better (simpler, clearer, less buggy) is exactly as Jos already gave four years ago:
k_minus(:,end:-1:1)
Helen Joan
Helen Joan am 30 Apr. 2019
is it possible to do this with a loop?

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