Question

I want to create a matrix like

A = [0 0 0 0 1;
     0 0 0 1 1;
     0 0 0 1 1;
     0 0 0 1 1;
     0 0 1 1 1;
     0 1 1 1 1]

based on a vector indicating how many ‘0’s should precede ‘1’s on each row:

B = [4 3 3 3 2 1]

Is there a loopless way to do this ?

Answer 1

You don’t mention in your question how the horizontal size of the array should be defined (the number of ones).

For predefined width you can use this code:

width = 5;

A = cell2mat(arrayfun(@(x) [ zeros(1,x), ones(1,width-x) ], B, 'UniformOutput', false)');

If you want that A has minimal width, but still at least one 1 in every row:

A = cell2mat(arrayfun(@(x) [ zeros(1,x), ones(1,max(B)+1-x) ], B, 'UniformOutput', false)');