[R] vector-factor operation

[Gabor Grothendieck]

Look at ?ave

ave(vec, Fac)
ave(vec, Fac, FUN = mean) # same
ave(vec, Fac, FUN = sd)

On 4/14/06, Murray Jorgensen <maj at stats.waikato.ac.nz> wrote:
> I found myself wanting to average a vector [vec] within each level of a
> factor [Fac], returning a vector of the same length as vec. After a
> while I realised that
>
> lm1 <- lm(vec ~ Fac)
> fitted(lm1)
>
> did what I want.
>
> But there must be another way to do this, and it would be good to be
> able to apply other functions than mean() in this way.
>
> Cheers, Murray
> --
> Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
> Department of Statistics, University of Waikato, Hamilton, New Zealand
> Email: maj at waikato.ac.nz                                Fax 7 838 4155
> Phone  +64 7 838 4773 wk    Home +64 7 825 0441    Mobile 021 1395 862
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>