MATLAB: How to allocate specified number randomly without using randsrc

randrandsrc

If I use randsrc, I can simply allocate specified number.
alphabet = [-3 -1 1 3];
defaultip = randsrc(1,N,alphabet) + j*randsrc(1,N,alphabet);
But If I don't use that(i.e not using communication tool box), how can I code it?
Thanks for your help!

Best Answer

This is one of the way I can think of 
alphabet = [-3 -1 1 3];
N = 50; 
idx = randi([1 numel(alphabet)], 1, N);
defaultip = alphabet(idx);
Result:
>> defaultip
defaultip =
  Columns 1 through 13
     3     3     3     1    -3    -1     3     1    -3     1    -1     3    -1
  Columns 14 through 26
    -1    -1     3    -1     3     3     1     1     1    -1     3    -1    -3
  Columns 27 through 39
    -3     3    -3     3    -1    -1    -1     1    -3    -1    -3    -3     3
  Columns 40 through 50
     3     3    -3     3     1    -1     1     1    -3    -3    -1
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