# Scan each column without for loop in MATLAB

I = [2 1]; A = [7 11 8 17];

How can I pick the right value in A without for loop? I is a vector of indices for each column in A. That is I(1) is 8 and I(2) = 11.

## Answers

Use sub2ind to generate linear indices based on the right row and column coordinates, then use these to index into A. In this case, I chooses the right row and you want to choose only one element for each column from the first up to the last:

ind = sub2ind(size(A), I, 1:numel(I)); out = A(ind);

# Example

>> I = [2 1]; >> A = [7 11 8 17]; >> ind = sub2ind(size(A), I, 1:numel(I)); >> out = A(ind); >> out out = 8 11