Use index from max() to extract matching values from another array

Suppose I have 2 n x m arrays A and B and I get the maximum element of each column of A with

[~,I]   = max(A)

Now I want to use I to extract the elements of B that correspond to the max element of each column of A.

For example (the example itself is of no particular interest)

A = rand(5)
B = A.^2
[~,I] = max(A)

Now I would like to have a one line command that extracts from B a row vector consisting of, for each j, the I'th element of column j.

Thanks!

Answer 1

[David Young]

Bmax = B(sub2ind(size(B), I, 1:size(B,2)))

[Leo Simon]

perfect, thanks very much

[Ram]

Hello,i am facing similar problem. my code is

 for w =1:length(mydata)
  %[~,I]= find(mydata{w, 5}(:,2)) = find(mydata{w, 1}(:,1));   
  for o = 1:length(mydata{w,5})
  index = find(mydata{w, 5}(:,2) == mydata{w, 1}(:,1)== o);
  mydata{w,7} = index;
  end
end

i have a cell which contains max and its index values in each row. Now i want to find max index values in another cell and extract those values( matrix 1*2, here i want to extract only 1st col value only). for ex. [M,I] = [2,295]. 295 index value of its max value in certain row, let say (6,26321) is the extracted index value in another cell. extract value is 6(1st col) similarly all other row cells matrix. Thanks in advance.

[Leo Simon]

I'm afraid I can't understand what you are trying to do. Could you augment the code snippet above to make it an MWE. This would require a sample specification of mydata. I also can't see the relationship between your text and the sample code.

[Ram]

thanks for responding, attached file as max with its indexand mydata has to find those index values and place it to a new cell. for example, i have index value 690, i am finding in mydata which has (8.1510,110.9065) but i need only first col value only for every index.