Get the numbers of rows where values change
10 views (last 30 days)
Show older comments
Maja Zdulska
on 16 Jul 2020
Commented: Maja Zdulska
on 16 Jul 2020
Hi,
I have an array of data, structured like this:
Latitude Longitude Height
23 54 7
23 54 3
23 54 8
23 55 4
23 55 2
24 54 0
24 54 1
24 55 2
24 55 7
How can I get the numbers of the rows where either Latitude or Longitude changes (so from the example above the output would be rows 3, 5 and 7)?
2 Comments
Image Analyst
on 16 Jul 2020
By the time you get down to row 3, nothing has changed yet. Row 3 is still the same as rows 1 and 2. Don't you mean 4, 6, and 8? Those are the actual rows where a change is first encountered.
Accepted Answer
Image Analyst
on 16 Jul 2020
By the time you get down to row 3, nothing has changed yet. Row 3 is still the same as rows 1 and 2. Don't you mean 4, 6, and 8? Those are the actual rows where a change is first encountered.
Try this:
m = [
23 54 7
23 54 3
23 54 8
23 55 4
23 55 2
24 54 0
24 54 1
24 55 2
24 55 7]
latChanged = [0; diff(m(:, 1))] % Logical -- use find() if you want row numbers.
lonChanged = [0; diff(m(:, 2))] % Logical -- use find() if you want row numbers.
eitherChanged = find(latChanged | lonChanged) % Row numbers where either lat OR lon changed.
More Answers (1)
David Hill
on 16 Jul 2020
b=diff(a);%a being your matrix
c=find(b(:,1)~=0|b(:,2)~=0);%c=3,5,7
0 Comments
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!