CODEWITHSUNDEEP
matlabmatrix
user1646349
user1646349

Reputation: 11

Randomly interchange columns of a matrix: Matlab

Suppose 

A = [1 2 3 5 7 9
     6 5 0 3 2 3]

I want to randomize the position of the matrix column position; to give B like so:

B = [3 9 1 7 2 5
     0 3 6 2 5 3]

How can I do this Matlab?

Upvotes: 1

Views: 355

Answers (3)

gnovice
gnovice

Reputation: 125854

You'll want to use the randperm function to generate a random permutation of column indices (from 1 to the number of columns in A), which you can then index A with:

B = A(:, randperm(size(A, 2)));

Upvotes: 0

Wolfie
Wolfie

Reputation: 30047

Now that code is formatted properly, it's clear the OP wants column preservation, although randperm is still the easiest option as given by HPM's answer. 

idx = randperm(size(A,2)); % Create list of integers 1:n, in random order, 
                           % where n = num of columns

B = A(:, idx);             % Shuffles columns about, on all rows, to indixes in idx

Upvotes: 0

High Performance Mark
High Performance Mark

Reputation: 78316

Try

B = A(randperm(length(A)))

Consult the documentation for explanations.

Upvotes: 1

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