Using a for- loop to extract a range of columns every n-columns

Hi all,

I have a 64x10000 matrix. Now I am trying to select certain columns within.

I want to select 200 columns every 2000 columns, so at the end my data would be a matrix of size 64x1000

Right now, my code looks like this :

data = rand(64,10000);

for w=1:5
    extract_data(w)=data(:, (2000*(w-1))+1:200)
      
      end
      

I hope that you can help me,

Thanks,

Answer 1

[Walter Roberson]

data = rand(64,10000);

startcols = 1:2000:size(data,2)-1999;
for w = 1:length(startcols)
    sc = startcols(w);
    extract_data(:,200*(w-1)+1:200*w)=data(:, sc:sc+199);
end

size(extract_data)

ans = 1×2

64 1000

[Carlos_conde]

thanks a lot

Walter Roberson, you are a lenged!

[Carlos_conde]

I was trying to understand your code again, and I think that I do not catch the reason for -1999

Can you please explain that?