CODEWITHSUNDEEP
sortingmatlab
Viktor
Viktor

Reputation: 141

Matlab - sorting a matrix

I think I can illustrate this best with an example: Suppose I have A = [ 1, 4, 2, 3; 0,-1, 2, -1]

I want to turn it into [1, 2, 3, 4; 0, 2, -1, -1]

i.e. keep columns intact, sort by entries in first row. How do I do this?

Upvotes: 1

Views: 301

Answers (1)

nibot
nibot

Reputation: 14958

The sortrows command does what you want:

>> A = [ 1, 4, 2, 3; 0,-1, 2, -1];
>> sortrows(A.').'   

ans =

     1     2     3     4
     0     2    -1    -1

You can also use the second return value from sort to get the column permutation necessary to turn your matrix into the one you want:

>> [~,ii] = sort(A(1,:))

ii =

     1     3     4     2

>> A(:,ii)

ans =

     1     2     3     4
     0     2    -1    -1

Upvotes: 2

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