How do i get the values of a 2D matrix based on column indices ?

I know this is a simple question, but I cant seem to find answers on this.

Given a 2D matrix of any size and a vector of indices, I want to index the elements in the matrix based on the column indices values in order.

Eg.
matrix = [1 2 3
          4 5 6
          7 8 9]  column indices = [1,3,1]

Output = [1,6,7] -> column index 1 = 1, column index 3 = 6, column index 1 = 7

Answer 1

[madhan ravi]

 Output = matrix(sub2ind(size(matrix), 1 : size(matrix, 1), column_indices))

[YI CHONG ONG]

Thank you for your help !

Answer 2

[Ameer Hamza]

Use sub2ind()

matrix = [1 2 3
          4 5 6
          7 8 9];
      
cols = [1 3 1];
idx = sub2ind(size(matrix), 1:size(matrix, 1), cols);
matrix(idx)

[YI CHONG ONG]

Thank you for your help !