[R] newbie: remove column with low mean from a matrix
J.R. Lockwood
lockwood at rand.org
Tue Mar 5 20:53:59 CET 2002
I'm sure there is a faster way, but
vec<-as.vector(apply(test,2,mean))
new.test<-test[,vec>=5]
should do what you need.
> I have a dataobject with several hundreds of columns. I want to remove
> columns with a mean of the column values below a certain value:
>
> > a<- c(1,2,3,4,5,6)
> > b<-c(2,4,6,8,10,12)
> > c<- c(3,6,9,12,15,18)
> > test<- as.matrix(cbind(a, b, c))
> > mean(a)
> [1] 3.5
> > mean(b)
> [1] 7
> > mean(c)
> [1] 10.5
>
> Say the "certain value" is 5, I would like a new matrix as follows:
>
> > new.test
> b c
> [1,] 2 3
> [2,] 4 6
> [3,] 6 9
> [4,] 8 12
> [5,] 10 15
> [6,] 12 18
J.R. Lockwood
412-683-2300 x4941
lockwood at rand.org
http://www.rand.org/methodology/stat/members/lockwood/
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