Selecting required elements from a matrix

1 visualizzazione (ultimi 30 giorni)
arjun
arjun il 15 Set 2014
Modificato: Guillaume il 15 Set 2014
I have a matrix A which contains 1's and 0's I wish to construct a new matrix B such that it has all the i,j values where A(i,j)=1, i.e B will be 2 X N matrix with its elements as the indices of the elements in matrix A who have a value of 1. for eg: A=[1,0,1,1,0] then B={[1,1];[1,3];[1,4]} Thanks
  1 Commento
Matt J
Matt J il 15 Set 2014
B={[1,1];[1,3];[1,4]} does not produce a 2xN matrix,
>> B={[1,1];[1,3];[1,4]}
B =
[1x2 double]
[1x2 double]
[1x2 double]

Accedi per commentare.

Accedi per rispondere a questa domanda.

Risposta accettata

Guillaume
Guillaume il 15 Set 2014
Modificato: Guillaume il 15 Set 2014
Is this what you're after ?
[row, col] = find(A);
B = [row col]';
I.e. use the two output version of find.
edit: The above answer assumes A is not a row vector. You can use Matt J fix to handle all cases or, if you know that A is a row vector:
[row, col] = find(A);
B = [row; col];
  2 Commenti
Matt J
Matt J il 15 Set 2014
Small fix, to handle the case when A is a row vector
B = [row(:) col(:)].';
Guillaume
Guillaume il 15 Set 2014
Oh yes, thanks!
I really hate that you can't write simple generic code in matlab because the shape of the output is not always the same.

Accedi per commentare.

Più risposte (0)

Categorie

Scopri di più su Matrices and Arrays in Help Center e File Exchange

Tag

Community Treasure Hunt

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

Start Hunting!

Translated by