How to order a matrix?
5 ビュー (過去 30 日間)
古いコメントを表示
Hello,
I have a matrix,
A=[ 100 5 0 ; 200 0 -5 ; 300 0 0 ; 300 5 0 ; -100 0 5 ; 300 0 0; 300 0 5];
I want to get,
A= [100 5 0; 200 0 -5 ; 300 0 0; 300 5 0 ; 300 0 5 ; -100 0 5];
I am writing code:
B= unique(A(:, 2:3),'rows');
then it's removing the first row as 5 0 is also repeted for the 4th row 300 5 0 but I need to keep the 1st row.
Is it possible to do?
4 件のコメント
Adam
2019 年 4 月 23 日
It's not really obvious from your example what you are trying to achieve in a more general case. Your example just removes one row (which can be removed by using just a simple unique as mentioned) and then orders the remaining ones in a fairly unintuitive manner with respect to how they started.
What are you actually trying to keep? If you are trying to keep all unique rows then what I wrote works fine, if you are really trying to only run a unique on the 2nd and 3rd columns then your version does that, but from what you say, that isn't what you want to do.
回答 (2 件)
Alex Mcaulley
2019 年 4 月 23 日
編集済み: Alex Mcaulley
2019 年 4 月 23 日
Try this:
[~,ia,~] = unique(A(:, 2:3),'rows','stable');
B = A(ia,:);
7 件のコメント
Alex Mcaulley
2019 年 4 月 23 日
Using round
If you want to round the first column:
A = [ 100 5 0 ; 200 0 -5 ; 300 0 0 ; 300 5 0 ; -100 0 5 ; 300 0 0; 300 0 5];
A(:,1) = round(A(:,1),-2);
[~,ia,~] = unique(A(:, 2:3),'rows','stable');
B = A(ia,:);
参考
カテゴリ
Help Center および File Exchange で Matrices and Arrays についてさらに検索
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!