How to combine vectors based on value?
11 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Good Afternoon,
Another quick question. Say I have a matrix,
B = [732145 732151 732168 0 0 0 0
284 281 297 0 0 0 0]
and
C =
[ 0 281 284 0 0 297 0
0 0 0 0 0 0 0]
I am trying to get it so that I have:
D = [0 281 284 0 0 297 0
0 732151 732145 0 0 732168 0].
Should I be using the [r c] kind of terminology. I keep almost getting there, I think, then I get confused.
Any thoughts would be greatly appreciated! or reading!
Thank you very much for any time!
0 Kommentare
Antworten (3)
Guillaume
am 16 Okt. 2015
Regarding your latest comment, a much simpler way of obtaining your D result, assumming that elements of B and C are uniques is:
assert(numel(unique(C)) == numel(C) && numel(unique(B)) == numel(B)); %does not work if elements are not unique
[values, ic, ib] = intersect(C, B);
D = zeros(numel(C), numel(B));
D(sub2ind(size(D), ic, ib)) = values;
If the values of B and C are not unique, you need an additional level of indirection through unique.
Andrei Bobrov
am 16 Okt. 2015
B = [4 5 6 7; 0 0 0 0; 0 0 0 0; 0 0 0 0];
C = [0; 5; 4];
D = B;
[ll,idx] = ismember(B(1,:),C);
D(sub2ind(size(D),1+idx(ll),find(ll))) = C(idx(ll));
0 Kommentare
Geoff Hayes
am 14 Okt. 2015
Do you wish to simply iterate over each element in the first row of C and, for those that are non-zero, check to see if it exists in the second row of matrix B and copy the the value from its first row into D? If so, try the following
D = C;
for k=1:size(C,2)
if C(1,k) ~= 0
[idx] = find(B(2,:)==C(1,k));
if ~isempty(idx)
D(2,k) = B(1,idx);
end
end
end
In the above, we just iterate over each column in the first row of C. If the element is non-zero then we use find to find that element of the second row of B that matches the value in C. If the returned index, idx, is non-empty then we set this value to the corresponding element of D.
Siehe auch
Kategorien
Mehr zu Logical 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!