random presentation of the columns of a matrix

Hello everyone! I am really new on matlab and I need to know how I can shuffle the columns of a matrix without changing the order of elements in every row. My code is this:

trialType = [1 2 3];

Examples = [4 5 6];

% Make a condition matrix

a = [trialType(1) Examples(1)]; %zeugos x & 1 fora

b = [trialType(1) Examples(2)]; %zeugos x & 2 fores

c = [trialType(1) Examples(3)]; %zeugos x & 3 fores

d = [trialType(2) Examples(1)]; %zeugos y & 1 fora

e = [trialType(2) Examples(2)]; %zeugos y & 2 fores

f = [trialType(2) Examples(3)]; %zeugos y & 3 fores

g = [trialType(3) Examples(1)]; %zeugos both & 1 fora

h = [trialType(3) Examples(2)]; %zeugos both & 2 fores

i = [trialType(3) Examples(3)]; %zeugos both & 3 fores

condMat = [a; b; c; d; e; f; g; h; i];

So disp(condMat) will give me:
   1     4
   1     5
   1     6
   2     4
   2     5
   2     6
   3     4
   3     5

I want something like this:

     1     6
     3     4
     1     4
etc.

Thanks on advance for your replies :)

Answer 1

[Guillaume]

First, a simpler way to generate your matrix:

trialType = [1 2 3];
Examples = [4 5 6];
[c1, c2] = ndgrid(trialType, Examples);
condMat = [c1(:), c2(:)];

Then, to randomly permute the rows of condMat, use randperm to generate a randomly ordered list of row indices:

condMat = condMat(randperm(size(condMat, 1)), :)

[Maria K]

It works perfectly!!! Thank you very much :) :)

Answer 2

[KSSV]

trialType = [1 2 3];

Examples = [4 5 6];

N = 10 ;
iwant = zeros(N,2) ;
for i = 1:N
    iwant(i,:) = [randsample(trialType,1) randsample(Examples,1)]  ; 
end
iwant

[Maria K]

Hmm maybe I didn't express myself correctly.. I want something like that:

   2     4
   2     5
   1     4
   2     6
   3     4
   1     5
   3     5
   1     6
   3     6
so we should get 1 with 4, 1 with 5, 1 with 6, 2 with 4, 2 with 5, 2 with 6, 3 with 4, 3 with 5, 3 with 6,    but the row of every combination (e.g. 1 with 4) should be random...

Thanks for your efford :)

Answer 3

[Matt J]

[m,n]=size(condmat);
condMat = condMat(randperm(m),:);