All negative number on bottom
3 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Andrea Stevanato
le 7 Mai 2018
Modifié(e) : Stephen23
le 7 Mai 2018
How i can sort matrix of numbers and put negative on bottom respecting the order of positive elements.
A = [1,-3,4;-2,5,6;4,2,1]
newA = [1,5,4;4,2,6;-2,-3,1]
0 commentaires
Réponse acceptée
Stephen23
le 7 Mai 2018
Modifié(e) : Stephen23
le 7 Mai 2018
>> A = [1,-3,4;-2,5,6;4,2,1]
A =
1 -3 4
-2 5 6
4 2 1
>> S = size(A);
>> [~,R] = sort(A<0,1);
>> C = ones(S(1),1)*(1:S(2));
>> X = sub2ind(S,R,C);
>> A(X)
ans =
1 5 4
4 2 6
-2 -3 1
2 commentaires
Stephen23
le 7 Mai 2018
Modifié(e) : Stephen23
le 7 Mai 2018
@Andrea Stevanato: basically we first detect the locations of the negative values, sort those locations, then create linear indices from those sorted locations. Lets have a look:
>> A = [1,-3,4;-2,5,6;4,2,1]
A =
1 -3 4
-2 5 6
4 2 1
>> S = size(A);
>> A<0 % logical index of negative values.
ans =
0 1 0
1 0 0
0 0 0
>> [~,R] = sort(A<0,1) % sort the columns of the logical index, returns row indices of each sorted column.
R =
1 2 1
3 3 2
2 1 3
>> C = ones(S(1),1)*(1:S(2)) % define column indices.
C =
1 2 3
1 2 3
1 2 3
>> X = sub2ind(S,R,C) % linear indices from row and column indices.
X =
1 5 7
3 6 8
2 4 9
>> A(X) % get elements of A using linear indices.
ans =
1 5 4
4 2 6
-2 -3 1
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Shifting and Sorting Matrices dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!