Nested for loop to parse specific array indices not working?

So I am writing a code that parses over binary data but I have to put the data into an array for this to work. Basically, the array has a size of 500 bits (1/0s) and I treat these bits as if it were a 50 by 10 frame of data. So in other words every tenth bit represents a new row. I need to only assign data to columns 5-8 of each row and I am assigning these values a value of 1 while the rest are all zeros. So I am writing my function like this:

function A = createData()

A=zeros(1,500); 

for i=5:10:110

      for j=8:10:110
          for k=i:j
              A(k)=1;
          end
      end
  end
  end

But I am getting every bit from position 5 to position 108 filled with 1s rather than just the 4 bits per row of ten. Anybody know why this doesn't work or what I am missing?

Answer 1

[Star Strider]

This works:

A = zeros(1,500);
Ar = reshape(A, {}, 10);
Ar(:,5:8) = 1;
A2 = zeros(1,500)
for k1 = 1:10:500
    A2(k1:k1+9) = Ar(fix(k1/10)+1,1:10);
end
A2

Note: My initial idea was to use Ar(:)' as the output but when I tried it, it didn’t produce the correct outuput.

A2 here produces:

A2 =

    Columns 1 through 19

       0     0     0     0     1     1     1     1     0     0     0     0     0     0     1     1     1     1     0

    Columns 20 through 38

       0     0     0     0     0     1     1     1     1     0     0     0     0     0     0     1     1     1     1

    Columns 39 through 57

       0     0     0     0     0     0     1     1     1     1     0     0     0     0     0     0     1     1     1 ...

which is what I believe you want.

[Seth]

Yup, thanks man

[Star Strider]

My pleasure!

Answer 2

[Image Analyst]

Do you mean like this:

A=zeros(1,500); % Initialize
a2 = reshape(A, [50, 10]) % Make into 2D array.
% Set columns 5-8, for all rows of the array, = 1
a2(:,5:8) = 1
% Reshape back into a row vector.
A = a2(:)'

[Seth]

Your method is doing the same exact thing mine is :/

Answer 3

[Andrei Bobrov]

ii = [5,8];
n=10;

v = zeros(1,500);
v(ii(1):n:end) = 1;
v(ii(2)+1:n:end) = -1;
A = cumsum(v);