Extracting info from multiple matrices

Robert (view profile)

on 17 Nov 2018
Latest activity Edited by Stephen Cobeldick

on 20 Aug 2019

madhan ravi (view profile)

Hello,
Wondering if anyone could suggest a simple way to extract info from matrix B based on Matrix A. I have two "correponding" matrices, info in Matrix A relate to info in Matrix B:
A=[1.02 0.2; 2.2 0.4; 0.5 0.6; 4.8 0.5; 1.5 0.3];
B=[58 63 27 1 478];
In this case, I need to identify the maximum value in Matrix A column 2, and then extract the associated info from Matrix B
Maxi=max(A(:,2));
Maxi =0.6, which correspond to 3rd row of Matrix A, and the to 3rd row of Matrix B, or in this case the value = 27
This is a very simple example, as my matrices are very large.
Your suggestions are very appreciated.

madhan ravi (view profile)

on 17 Nov 2018
Edited by madhan ravi

madhan ravi (view profile)

on 17 Nov 2018

A=[1.02 0.2; 2.2 0.4; 0.5 0.6; 4.8 0.5; 1.5 0.3];
B=[58 63 27 1 478];
[value,idx]=max(A(:,2))
B(idx) %corresponding value in B

Show 1 older comment

on 17 Nov 2018
Anytime :)
M.Prasanna kumar

M.Prasanna kumar (view profile)

on 20 Aug 2019
here only two matrices are there A and B
suppose if there are 10 matrices A, B,C,D,E,F,G,H,IJ and same operation sholud be done as u explaines in the code how to do that?? please help
Stephen Cobeldick

Stephen Cobeldick (view profile)

on 20 Aug 2019
M.Prasanna kumar wrote: "suppose if there are 10 matrices A, B,C,D,E,F,G,H,IJ and same operation sholud be done as u explaines in the code how to do that?"
As always in such situations, the solution is to organize the data in one array, e.g. a cell array, and then trivially use indexing (which is simple and efficient). Here is an example using cellfun, but you could easily use a loop too:
[~,idx] = max(A)
out = cellfun(@(m)m(idx),{B,C,D,E,F,G,H,I,J},'uni',0)
Adjust the dimensions and indexing to suit your arrays.
See also original question from M.Prasanna kumar: