[R] question about a small "for" loop
Wolfgang Huber
huber at ebi.ac.uk
Mon Jul 14 23:33:38 CEST 2008
Christopher W. Ryan wrote:
> R 2.5.1 on WinXP
>
> I'm trying to create new variables in a dataframe called jaw, as powers
> of jaw$age up to the sixth power, and name them
>
> jaw$age.(--the digit corresponding to the power--)
>
> Obviously none of these work (silly for me to try, I suppose):
>
> for (i in 2:6) {
> jaw$age.'i' <- jaw$age^i
> }
>
> for (i in 2:6) {
> jaw$age.i <- jaw$age^i
> }
>
> for (i in 2:6) {
> jaw$age."i" <- jaw$age^i
> }
>
> What is the proper syntax to create and name these variables all at once?
>
> Thanks.
>
> --Chris
for (i in 2:6)
jaw[[paste("age", i, sep="^")]] = jaw$age^i
or
m = outer(jaw$age, 2:6, "^")
colnames(m) = paste("age", 2:6, sep="^")
jaw = cbind(jaw, m)
Best wishes
Wolfgang
--
----------------------------------------------------
Wolfgang Huber, EMBL-EBI, http://www.ebi.ac.uk/huber
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