[R] Count values in a dataframe with respect to groups

[Felipe Carrillo]

Here is an option:

grp = c(1,1,1, 1,2, 2,2)
 val = c(2,1,5,NA,3,NA,1)
 dta = data.frame(grp=grp, val=val)
ddply(dta,"grp",summarise,count=length(na.omit(val)))
 
Felipe D. Carrillo
Supervisory Fishery Biologist
Department of the Interior
US Fish & Wildlife Service
California, USA



----- Original Message ----
> From: Marcus Drescher <drescher at tum.de>
> To: "r-help at r-project.org" <r-help at r-project.org>
> Sent: Fri, October 8, 2010 8:04:40 AM
> Subject: Re: [R] Count values in a dataframe with respect to groups
> 
> Thanks! It works great.
> 
> One more question: how would I have to set the formula if I would have the 
>columns to count (val1 and val2)?
> 
> 
> Betreff: Re: [R] Count values in a dataframe with respect to groups
> 
> Try this:
> 
> aggregate(val ~ grp, dta, length)
> 
> On Fri, Oct 8, 2010 at 11:28 AM, Marcus Drescher <drescher at tum.de> wrote:
> Dear all,
> 
> I am looking for a function to count values belonging to a class within a 
>dataframe (and ignore NAs).
> 
> grp = c(1,1,1, 1,2, 2,2)
> val = c(2,1,5,NA,3,NA,1)
> 
> dta = data.frame(grp=grp, val=val)
> 
> The result should look like:
> 
> grp count
>  1    3
>  2    2
> 
> At the moment, I am trying to find a function for FUN in aggregate, but with no 
>success. Can anybody help me?
> 
> Thanks in advance.
> Marcus
> 
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> 
> -- 
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
> 
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