R: [R] extracting columns with NA's

[Vito Muggeo]

If I have understood what you mean, you can use the (surely non-optimal)
code:

#build a matrix ....
A<-matrix(1:20,nrow=5)
A[2,4]<-NA
A[,3]<-rep(NA,nrow(A))

#count the missing value in each column
fi<-apply(A,2,function(x)sum(is.na(x)))

#exclude column(s) having a number of NA equal to nrow(A). Of course you can
modify the "==" as well as "nrow(A)"
A1<-A[!which(fi==nrow(A)),]


Hope this help you
best,
vito

----- Original Message -----
From: antonio rodriguez <arv at ono.com>
To: R-help <r-help at stat.math.ethz.ch>
Sent: Friday, September 19, 2003 11:58 AM
Subject: [R] extracting columns with NA's


> Hi All,
>
> How do I can delete from a matrix (or array) only those columns which have
> all their values set to NA?
>
> Cheers
>
> Antonio Rodriguez
> ---
>
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