Finding the ratio of numbers in an array

9 views (last 30 days)
Benjamin Cowen
Benjamin Cowen on 4 Mar 2020
Edited: Rik on 4 Mar 2020
I access my array as:
data{1, i}(:,2)
So it is in the second column of data{1,i}
I have data in columns 3 and 4 already. I would like to make a column 5. I want column 5 to be the value in column 2 divided by the value in column 2 but 30 cells up. This means the first 30 values cannot be defined since we cannot compare to 30 cells prior. I keep trying this but I either get an array of zeros, or a single value. Can anyone help?
For instance, this does not work:
for j =31:1:1000
rois=data{1, i}(j,2)/data{1, i}(j-30,2)
end
  2 Comments
Benjamin Cowen
Benjamin Cowen on 4 Mar 2020
Yeah, it should be 1, sorry about that. I tried 1 at first and it got hung, so i assumed i was doing something wrong

Sign in to comment.

Answers (1)

Rik
Rik on 4 Mar 2020
Edited: Rik on 4 Mar 2020
rois=data{1, i}(31:end,2)./data{1, i}(1:(end-30),2);
In your current loop you are overwriting your result every iteration, you should have used indexing instead, skip the loop entirely.

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!