清空筛选条件
清空筛选条件

non zero rows per column

3 次查看（过去 30 天）
babis
babis 2013-12-5
编辑： Alfonso Nieto-Castanon 2013-12-6
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 个评论
dpb
dpb 2013-12-5
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.
Azzi Abdelmalek
Azzi Abdelmalek 2013-12-5
Babis, can you explain?

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Alfonso Nieto-Castanon
编辑：Alfonso Nieto-Castanon 2013-12-6
If I understand your question correctly this should do:
[a,b]=sort(A>0,1,'descend');
B=a'.*b';

更多回答（2 个）

dpb
dpb 2013-12-5
"Deadahead" solution...
B=zeros(size(A))';
for i=1:size(A,2)
ix=A(:,i)~=0;
B(i,ix)=find(A(:,i));
end
  2 个评论
babis
babis 2013-12-5
i think that this is really close to what i want, thank you
dpb
dpb 2013-12-5
编辑：dpb 2013-12-5
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...

请先登录，再进行评论。

José-Luis
José-Luis 2013-12-5
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;

类别

在 Help Center 和 File Exchange 中查找有关 Matrices and Arrays 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by