[R] Row means of matrix.

[arun]

HI,
Try this:
 m[m==0]<-NA
apply(m,1,mean,na.rm=T)
#[1] 2.5 NaN 1.0
A.K.



----- Original Message -----
From: Yingwei Lee <dingayinga at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Friday, August 17, 2012 11:28 PM
Subject: [R] Row means of matrix.

Hi all,
          I'm just having trouble getting row means of a matrix which
contain zero.
For example.

m=matrix(c(1:4, c(0, 0, 0, 0), c(1, 0, 1, 1)), nc=4, byrow=TRUE)

I want to be able to calculate means for non-zero elements for each row.

## what i have is this
apply((m[apply(m != 0, MARGIN=1, any),]), 1, mean)
## which returns
[1]  2.50  0.75

### what i want to get returned is this
[1] 2.50  *1

*meaning that the last row calculated the mean ignoring the zero. Anyone
got any ideas?

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