how do i select a number from a set randomly

I want to select 1 or -1, my code now looks like this:

if true
  % code
for i = 1:101
  for j = 1:5
      %action may be -1 or 1 
      ac = [-1,1]; 
      posA = randi(length(ac));
      Asimulac(i,j) = ac(posA);

        posB = randi(length(ac));
        Bsimulac(i,j) = ac(posB);
    end
end
  end

It works but posA and posB keeps being the same for every loop in j=1:5, which is not what I want. In otherwords Asimulac(i,j) = Bsimulac(i,j). How do I really randomly draw from the set [-1,1]?

Answer 1

[Stephen23]

   V = [-1,+1]; % or any set of values
   V(randperm(numel(V),1)) % pick one out of the set

Answer 2

[James Tursa]

If you are just interested in the values -1 and 1, you could do something like this:

Asimulac = round(rand(101,5))*2-1;
Bsimulac = round(rand(101,5))*2-1;