How to mix order of rows in a matrix?

With randperm it is possible to mix order of the components of a vector v: v(randperm(lenght(v)))
But how to mix rows in a matrix?

 Réponse acceptée

Jos (10584)
Jos (10584) le 25 Fév 2015
Very much the same procedure;
M = repmat(1:10,4,1).' % example data
r = randperm(size(M,1)) % permute row numbers
Mout = M(r,:)

4 commentaires

Mr M.
Mr M. le 25 Fév 2015
and how to apply the same permutation to a vector?
Huh? You did that in your question. How is this different than that? To review:
v = [1,2,3,4,5,6,7,8]
v = v(randperm(length(v)))
Mr M.
Mr M. le 25 Fév 2015
but I need the same permutation used for the matrix rows!
Assuming that your matrix has the same number of rows as your vector has elements, then you just need to use the same indices for both the matrix and the vector:
r = randperm(size(M,1)) % generate your indices.
Mout = M(r,:) % rearrange the rows of a matrix
Vout = V(r) % rearrange the elements of a vector
Look how they both use the same permutation r. You should read about indexing.

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