[R] averaging rows on a data.frame according to a factor

[Rui Barradas]

Hello,

Try the following.

aggregate(cbind(V2, V3) ~ V1, dat, FUN = mean)


Hope this helps,

Rui Barradas

Em 22-11-2013 21:43, john d escreveu:
> Dear all,
>
> I apologize for the newbie question, but I'm stuck.
>
> I have a data frame in the following form:
>
> dat<-as.data.frame(cbind(c("a","a","a","b","b"), c(1,2,3,3,2),c(4,3,5,4,4)))
>
> I need a way to generate a new dataframe with the average for each factor.
> The result should look like:
>
> res<-as.data.frame(cbind(c("a","b"), c(2,2.5),c(4,4)))
>
> Any help would be greatly appreciated.
>
> Jonathan
>
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>
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