MATLAB: Obtain data using columns data indices

columnsrows

i have data A=( 3,5,3,1,4 ) in a column and

B=[ 4 6 9 1 3

2 7 2 5 7

7 3 1 8 2

4 1 6 9 1

2 5 8 3 6]

and i want: as in A first element is 3 and for this i want to get first element of column 3 row 1 from B which is 9. The second element of A is 5 and for this i want to get the the 2nd element of column 5 and row 2 from B which is 7 ,and do the process for all other elements . how to do this? the requried elememts are bold and underlined

any help will be really appriciated………thanks in advance

Best Answer

 B(sub2ind( size(B), 1:length(A), A))

Related Solutions

MATLAB: Columns data to reference rows data

It really doesn't help if you invent your own syntax for your examples instead of using valid matlab syntax. It also doesn't help if you write .5 in you example then say that the value is 5 (10 times more).

Assuming I understood correctly:

A = [1, 4, 2, 5, 4]  %note that this is a ROW vector not a column, but that doesn't matter anyway
B = [3 5 6 3 1
     4 2 7 9 2
     3 3 4 8 9
     5 1 4 5 6
     2 3 6 8 3];   %I'm assuming all these . in your example are not meant to be there. The values don't matter anyway
%option 1:
result =  B(sub2ind(size(B), A, A))
%option 2:
diagB = diag(B).';
result = diagB(A)

MATLAB: Removing lowest value in each line from a matrix

Here's one way. Possibly not the most compact, but easy to understand, and there's something to be said for that.

A = [0 7 7 4; -3 4 10 12; 10 12 12 4];
[rows, columns] = size(A);
B = zeros(rows, columns-1);
for row = 1 : rows
  thisRow = A(row, :); % Get this one row.
  [~, indexOfMin] = min(thisRow); % Find index of the min.
  thisRow(indexOfMin) = [];  % Delete the min element.
  B(row, :) = thisRow; % Stuff it into B
end
% B is the output.

Andrei will provide a one-liner shortly, I'm sure.

Best Answer

Related Solutions

MATLAB: Columns data to reference rows data

MATLAB: Removing lowest value in each line from a matrix

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