MATLAB: How to sum part of a column

sum parts 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

Best Answer

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 ) )

Related Solutions

MATLAB: Sum

I am a little confused, do you mean like this:

Y = reshape(1:18,6,3)  % A manageable dimension.
Y_1 = sum(Y,2)

So in your case it would be

Y_1 = sum(Y,2).';

Or do you mean, more like this:

Y = 1:18
Y_1 = sum(reshape(Y,3,6))

So in your case it would be

Y_1 = sum(reshape(Y,320,467))

MATLAB: Him I have a 9 * 9 matrix and I want to reduce each row in the column, the average of that column. How to do this

Try this:

a=[3 2 3;1 2 3; 2 2 3]
b = repmat(mean(a), [size(a, 1), 1])
aMinusB = a-b

You get

a =
     3     2     3
     1     2     3
     2     2     3
b =
     2     2     3
     2     2     3
     2     2     3
aMinusB =
     1     0     0
    -1     0     0
     0     0     0

I really don't know how you're getting your a-b. Maybe you can explain.

Best Answer

Related Solutions

MATLAB: Sum

MATLAB: Him I have a 9 * 9 matrix and I want to reduce each row in the column, the average of that column. How to do this

Related Question