How to retain only the rows of a matrix based on the unique numbers in the first column of the matrix?
1 Ansicht (letzte 30 Tage)
Ältere Kommentare anzeigen
Mohammad Sayeed
am 22 Apr. 2014
Kommentiert: Mohammad Sayeed
am 23 Apr. 2014
Hello guys Say that a=[1 3 3; 1 4 3; 2 4 3; 2 5 2; 2 4 2; 3 2 1; 4 3 4; 4 3 2] I need to keep the rows where I have only unique numbers in the first column of the matrix. That means I want to have this matrix a= [1 3 3; 2 4 3; 3 2 1; 4 3 4]. Or I also need to get [1 4 3; 2 4 2; 3 2 1; 4 3 2]. That means retaining the last unique row (based on only the first column) instead of the first. Are they possible? please help.
Kind regards
Sayeed
0 Kommentare
Akzeptierte Antwort
Azzi Abdelmalek
am 22 Apr. 2014
Bearbeitet: Azzi Abdelmalek
am 22 Apr. 2014
[ii,jj,kk]=unique(a(:,1),'stable');
out1=a(jj,:)
out2=cell2mat(accumarray(kk,1:numel(kk),[],@(x) {a(max(x),:)}));
Weitere Antworten (1)
Andrei Bobrov
am 22 Apr. 2014
Bearbeitet: Andrei Bobrov
am 22 Apr. 2014
[~,b] = unique(a(:,1),'first');
out1 = a(b,:);
out2 = a([b(2:end)-1;size(a,1)],:);
or
[~,b1] = unique(a(:,1),'first');
[~,b2] = unique(a(:,1),'last');
out1 = a(b1,:);
out2 = a(b2,:);
Siehe auch
Kategorien
Mehr zu Multidimensional Arrays finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!