[R] scaling-centering a vector using an index

[J.R. Lockwood]

> x<-rnorm(10,3)
> f1<-rep(c("a","b"),5)
> f2<-rep(c("c","d"),c(5,5))
> unsplit(lapply(split(x,list(f1,f2)),scale),list(f1,f2)) ##first call
> group<-paste(f1,f2)
> unsplit(lapply(split(x,group),scale),group) ##second call

In your first call, the object

lapply(split(x,list(f1,f2)),scale)

is a list that knows nothing about "f1" and "f2"

thus you can't unsplit that list with respect to those factors.

J.R. Lockwood
412-683-2300 x4941
lockwood at rand.org
http://www.rand.org/methodology/stat/members/lockwood/

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