Taking Average of Nonzero Elements

Hi everyone,

I have got 2 questions, I hope someone can help me.

The first one is, I have a matrix A where

A = 1   2  3  4
    5   6  7  8
    9  10 11 12
    13 14 15 16

Then I apply the following

A = A>6 & A<11
[r,c,v] = find(A)

Doing that in the end I will have the information of indices that belong to those elements fulfilling the condition A>5 & A<12 in vectors r and c. Now I have another matrix B of the same dimensions as A.

B = 54 32 13  5
     1 10 45 24
     4 44  2 15
    66 26 17 89

I want to choose only elements of B having the same indices as the elements in A that fulfilled the previous condition, leaving the other elements as zero. But if a row of B doesn't have such element matching what was mentioned above then it's truncated. So in the end I will have

result = 0  0 45 24
         4  44 0  0

My last problem is simply how to take the average value on each element of matrix 'result' ignoring zeros, so what I will get is

mean = 34.5
         24

I will really appreciate any help. Thanks in advance.

Answer 1

[Matt J]

L=(A>6 & A<11);
means=sum(B.*L,2)./sum(L,2);
 means=means(~isnan(means))

[Imam]

Allright, it does help. Thanks a lot Matt.