How to sum part of a column?

Hi. I am new to Matlab.

Does anybody know how I can calculate the column sum of row 1 and 2 in column 3 in the follwoing matrix (3+6)?

     1     2     3
     4     5     6
     7     8     9

Answer 1

[Kye Taylor]

If your matrix is called A, then rows 1 and 2 in column 3 can be identified with the syntax

A( 1:2, 3 )

So sum it using the command

sum( A( 1:2, 3 ) )

[Karl]

Thank you very much!

Answer 2

[Birabhadra Rout]

if i have a matrix of vecor 1 2 1 3 1 4 2 2 2 3 2 4 and i want to add each number in 2nd column with having similar data in 1 st column and i want to save it as 1 9 2 10 then how to do it ?