How to increment data steps in a loop?

Hello, I am trying to look at a set of data 7000 entries long and I want to break it into intervals of 30. The first will look at 1-30, next 2-31 and so on. How can I use a "for" or "while" loop to so? I know its all in how I use the conditions, but I have not had any luck so far. Thank you!

Answer 1

[Azzi Abdelmalek]

A=rand(7000,1)
for k=1:7000-30+1
  b=A(k:k+29);
  % do
end

Answer 2

[Ry]

So now that I have it incremented how can I get the out put, b, to show that this is the 400th time through the loop? Can matlab tell me, or do I need to ask matlab?