non zero rows per column
1 visualizzazione (ultimi 30 giorni)
Mostra commenti meno recenti
babis
il 5 Dic 2013
Modificato: Alfonso Nieto-Castanon
il 6 Dic 2013
i have a matrix. suppose
A=[1 0 8; 0 0 2; 3 0 5; 4 8 0; 0 5 3; 6 1 3; 1 6 5; 0 7 1]
and i want to get the non zero rows per column in a new matrix. in my example that will be
B = [ 1 3 4 6 7 0 0 0; 4 5 6 7 8 0 0 0; 1 2 3 5 6 7 8 0]
( if A=(m,n) B will be B=(n,m) )
2 Commenti
dpb
il 5 Dic 2013
Use the "Code" button (or insert couple spaces in front of code lines on separate line w/ blank line between it and preceding text) to format the code to be legible.
Risposta accettata
Alfonso Nieto-Castanon
il 5 Dic 2013
Modificato: Alfonso Nieto-Castanon
il 6 Dic 2013
If I understand your question correctly this should do:
[a,b]=sort(A>0,1,'descend');
B=a'.*b';
Più risposte (2)
dpb
il 5 Dic 2013
"Deadahead" solution...
B=zeros(size(A))';
for i=1:size(A,2)
ix=A(:,i)~=0;
B(i,ix)=find(A(:,i));
end
2 Commenti
dpb
il 5 Dic 2013
Modificato: dpb
il 5 Dic 2013
It reproduces you example (w/ the exception of the extra row of zeros which I presumed was an error). If that is indeed wanted, then just augment the end result. You can, of course, with care to keep parens nested properly, do away with the intermediary I used for clarity of exposition. So what is on "really close" about it instead of "dead on"?
It should be reasonably easy to accumarray or otherwise vectorize it w/ the idea given altho it's not convenient here at the moment...
José-Luis
il 5 Dic 2013
your_mat = ndgrid(1:size(A,1),1:size(A,2));
your_mat(A==0) = 0;
your_mat(your_mat==0) = Inf;
your_mat = sort(your_mat);
your_mat(your_mat==Inf) = 0;
0 Commenti
Vedere anche
Categorie
Scopri di più su Matrices and Arrays in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!