MATLAB: Mean value of a particular portion of a matrix

Question

Hi, I have problem regarding matrix average.

suppose I have two matrix A and B as follows:

A =

     1     2     3
     3     3     6
     4     6     8
     4     7     7
B =
     2     2     3
     2     3     6
     4     6     2
     4     7     2

I need the mean value of A where value of B is 2. i.e mean value of the positions : (1,1) (1,2)(2,1)(3,3)(4,3)

is there any easy way to do this?

Answer 1

variant

mean(A(B==2));