# Create a vector by selection randomly vectors

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Hi all,
I have 4 vectors
A=[1 2 3 4 5];
B=[0 2 5 6 19];
C=[0 0 1 3 0];
D=[1 0 1 15 0];
And I want to create vectors by randomly selecting from the list above, so that I take something like:
Vector1=[B;C;D;A]
Vector2=[C;D;A;B]
Vector3=[A;D;C;B]
.
.
.
etc.

Stephan on 5 Nov 2018
Edited: Stephan on 5 Nov 2018
A=[1 2 3 4 5];
B=[0 2 5 6 19];
C=[0 0 1 3 0];
D=[1 0 1 15 0];
pool = [A; B; C; D];
n = 10 % Number of vectors to create
for k = 1:n
idx = randperm(4);
result(k,:) = [pool(idx(1),:), pool(idx(2),:), pool(idx(3),:), pool(idx(4),:)]
end
This code stores the created vectors in the lines of a Matrix. Access them with:
vector_1 = result(1,:)
vector_2 = result(2,:)
.
.
.
vector_n = result(n,:)
Best regards
Stephan
Nikolas Spiliopoulos on 5 Nov 2018
thanks a lot! it's working..!!

Stephen on 5 Nov 2018
Edited: Stephen on 5 Nov 2018
Having separate vectors is a pain to work with, so the first thing to do is to put them into one matrix M:
>> M = [1,2,3,4,5;0,2,5,6,19;0,0,1,3,0;1,0,1,15,0]
M =
1 2 3 4 5
0 2 5 6 19
0 0 1 3 0
1 0 1 15 0
>> N = 7; % how many output matrices
>> [~,R] = sort(rand(N,size(M,1)),2);
>> C = cellfun(@(r)M(r,:),num2cell(R,2),'uni',0);
>> C{:}
ans =
0 0 1 3 0
1 0 1 15 0
0 2 5 6 19
1 2 3 4 5
ans =
1 2 3 4 5
0 2 5 6 19
1 0 1 15 0
0 0 1 3 0
ans =
1 2 3 4 5
1 0 1 15 0
0 0 1 3 0
0 2 5 6 19
ans =
1 2 3 4 5
1 0 1 15 0
0 2 5 6 19
0 0 1 3 0
ans =
0 0 1 3 0
1 0 1 15 0
1 2 3 4 5
0 2 5 6 19
ans =
0 2 5 6 19
0 0 1 3 0
1 0 1 15 0
1 2 3 4 5
ans =
0 2 5 6 19
1 0 1 15 0
1 2 3 4 5
0 0 1 3 0

madhan ravi on 5 Nov 2018
Edited: madhan ravi on 5 Nov 2018
EDITED
A=[1 2 3 4 5]; B=[0 2 5 6 19]; C=[0 0 1 3 0]; D=[1 0 1 15 0];
vectors = [A;B;C;D];
n = 10 ; % specify n to create n number of vectors
VECTORS = cell(1,n); %PREALLOCATION
for i = 1:n
VECTORS{i}=[vectors(randsample((1:4),4) ,:)];
end
celldisp(VECTORS)
Stephen on 5 Nov 2018
Note that randi can repeat values in its output array, so this answer does not match the examples given (which do not repeat any rows and are all row permutations of the same matrix).
For example:
>> randi([1,4],2,2)
ans =
1 4
1 4
Would return A,A,D,D: where are B and C ?
One solution is to use randperm, as Stephan Jung's answer shows.