Extracting info from multiple matrices

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.

Answer 1

[madhan ravi]

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

[Robert]

Thank you for your quick response, very appreciated!

[madhan ravi]

Anytime :)

[M.Prasanna kumar]

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

[Stephen23]

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:

https://www.mathworks.com/matlabcentral/answers/476804-how-to-increase-the-number-in-for-loop-as-i-explained-below