how select random elements of array without replacement

I have a matrix A(1*N).[a11 a12 a13 a14 a15 a16 a17 .....] first,I want to select random m1 member of A without replacement .then I want to select m2 member without replacement that don't select befor step. and I want that don't select a14 in any step. can anybody help me to write matlab code of it?

[zohre saeedi]

how I know that don't select a14? and I want member of m1 be different from member of m2

Answer 1

[Stephen23]

The easiest way to do this is to use randperm: this provides a random selection without replacement. Note that randi uses replacement, so is not useful for your task.

Something like this:

>> A = 1:23;
>> excl = 4; % indices to exclude
>> B = A(~ismember(1:numel(A),excl));
>> idx = randperm(numel(B));

Where B contains all values of A except the elements at locations given in excl, and idx contains random indices without replacement for every element in B. Thus you can easily use these indices in a loop:

for k = 1:numel(B)
    B(idx(k))
end

[zohre saeedi]

thanks for your help. your answer is very good.