How to create an an array of unknown size?

Say, I have an array A of size 100 consisting of 0's and 1's. I need to create a smaller array consisting only of the 1's. At start, I don't know the number of 1's in the original array. Basically, I want to create the subset-array element-by-element as I loop over the elements of the original array and checking for 1's.Any help appreciated. Thanks, Preetam

[per isakson]

"create the subset-array element-by-element as I loop over the elements " &nbsp is that a requirement or a hint?

Answer 1

[Star Strider]

I’m not quite sure what you want.

Here are two possibilities:

Array = randi([0 1], 1, 100);
OnesArray = Array(Array==1)             % Ones Array
ElemArray = find(Array);                % Indices Of Ones In ‘Array’

Answer 2

[Matt J]

I'm also not sure what you want, but it might be worth being aware of the nonzeros() command,

 B=nonzeros(A);

Or, since you know that A consists only of zeros and ones,

B=ones(nnz(A),1);