Converting a the result vector from logical indexing into a matrix possible or unnescesary?

1 view (last 30 days)
Hello everyone,
I need to extract rows of a matrix with a certain value in one column. At the moment I am using logical indexing i this way:
c=A(:,2)==3; T=A([c,c,c,c]);
The problem I have is that T is a vector, with the columns added end to end, but I need it as a matrix.
Does Matlab provide an easy way to convert such a vector to a matrix or is there another easy way to extract the rows into a matrix?
Thank you everybody.

Accepted Answer

Andrei Bobrov
Andrei Bobrov on 4 Dec 2013
T = A(A(:,2) == 3,:);

More Answers (1)

Jos (10584)
Jos (10584) on 7 Dec 2013
Often, you get some insight when you remove the semi-colons
A = [1 2 3 4 ; 11 3 13 14 ;21 22 23 24 ; 41 3 43 44] % example data
c = A(:,2)==3
T = A(c,:)
if T is empty, there are simply no rows that have a value of 3 in the second column.
  1 Comment
Daniel
Daniel on 7 Dec 2013
Sorry was using the wrong matrix. The first answer works just fine. To much data and I lost track of what is what. Thanks to both of you.

Sign in to comment.

Community Treasure Hunt

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

Start Hunting!