[R] calculate sd for each row on some columns of a dataframe
Henrique Dallazuanna
wwwhsd at gmail.com
Thu Feb 28 12:34:52 CET 2008
Try this:
lapply(list(letters[1:3], letters[2:4]), function(x)apply(df[,x], 1, sd))
On 28/02/2008, Albert Vilella <avilella at gmail.com> wrote:
> Hi,
>
> I've got a dataframe like this:
>
> df = data.frame(a=rnorm(100,1),b=rnorm(100,10),c=rnorm(100,100),d=rnorm(100,-100))
>
> and I want to calculate sd1 for (a,b,c) for each entry, and sd2 for
> (b,c,d) for each entry.
>
> I don't seem to find the answer using aggregate or apply,
>
> How can I do this?
>
> Thanks in advance,
>
> Cheers,
>
> Albert.
>
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--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O
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