How do I index into a matrix with a vector to extract the jth column for each row?
1 Ansicht (letzte 30 Tage)
Ältere Kommentare anzeigen
Richard
am 3 Mai 2016
Beantwortet: Star Strider
am 3 Mai 2016
Is there an easy way to index into a matrix with a vector to extract the jth column of the matrix for each row? As an example, lets take the 4 x 4 matrix created by
A = magic(4);
A =
16 2 3 13
5 11 10 8
9 7 6 12
4 14 15 1
I have a vector which describes which columns I'd like to extract:
ii = [1; 2; 1; 2]
ii =
1
2
1
2
Is there a straightforward way of indexing into the matrix to return the vector:
result =
16
11
9
14
0 Kommentare
Akzeptierte Antwort
Star Strider
am 3 Mai 2016
There is. Use the sub2ind function:
A = magic(4);
ii = [1; 2; 1; 2];
ix = sub2ind(size(A), [1:4]', ii);
result = A(ix)
result =
16
11
9
14
0 Kommentare
Weitere Antworten (1)
Siehe auch
Kategorien
Mehr zu Matrix Indexing 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!