[R] extracting columns with NA's

[Peter Wolf]

antonio rodriguez wrote:

>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
>---
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>  
>
Try:

 > x<-matrix(1:16,4,4)
 > x[col(x)>=row(x)]<-NA
 > x[,! apply(x,2,function(x) all(is.na(x))) ]
     [,1] [,2] [,3]
[1,]   NA   NA   NA
[2,]    2   NA   NA
[3,]    3    7   NA
[4,]    4    8   12

Peter Wolf