# Re: [R] Group level frequencies

From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.be>
Date: Wed, 16 Jul 2008 11:05:09 +0200

well, I'm not completely sure I understand what you want to compute but you may try the following:

data.ml <- data.frame(i = 1:8, g = factor(c(1,1,1,2,2,3,3,3)),

var1 = c(3,3,3,4,4,4,4,4), var2 = c(8,8,8,2,2,4,4,4))

```################
```

data.ml[!duplicated(data.ml\$g), -1]
# or
t(sapply(split(data.ml[c("var1", "var2")], data.ml\$g),

colMeans))

I hope it helps.

Best,
Dimitris

Dimitris Rizopoulos
Biostatistical Centre
School of Public Health
Catholic University of Leuven

```Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm

```
• Original Message ----- From: "Kunzler, Andreas" <a.kunzler_at_bzaek.de> To: <r-help_at_r-project.org> Sent: Wednesday, July 16, 2008 10:21 AM Subject: [R] Group level frequencies

> Dear List,
>
> I have Multi-level Data
>
> i= Indivitual Level
> g= Group Level
> var1= First Variable of interest
> var2= Second Variable of interest
>
> and I want to count the frequency of "var1" and "var2" on the group
> level.
>
> I found a way, but there must be a much simpler way.
>
> data.ml <-
> data.frame(i=c(1:8),g=as.factor(c(1,1,1,2,2,3,3,3)),var1=c(3,3,3,4,4,4,4
> ,4), var2=c(8,8,8,2,2,4,4,4))
>
> therefore the data looks like
> i g var1 var2
> 1 1 1 3 8
> 2 2 1 3 8
> 3 3 1 3 8
> 4 4 2 4 2
> 5 5 2 4 2
> 6 6 3 4 4
> 7 7 3 4 4
> 8 8 3 4 4
>
> 1. I used tapply to get the (Group)mean of var1 and var2 in separate
> Equations. The result will be two one-dimensional Array with
> rownames.
> 2. I Transformed the Arrays in two data.frames
> 3. I merged the data.frames
>
> d.var1 <-
> data.frame(id=rownames(tapply(data.ml\$var1,data.ml\$g,mean)),var1=as.nume
> ric(tapply(data.ml\$var1,data.ml\$g,mean)))
>
> d.var2 <-
> data.frame(id=rownames(tapply(data.ml\$var2,data.ml\$g,mean)),var2=as.nume
> ric(tapply(data.ml\$var2,data.ml\$g,mean)))
>
> data.gl <- d.var1
> data.gl\$var2 <- d.var2\$var2
>
> By putting the data.frames d.var1 and d.var2 together in a new
> data.frame data.gl I would like to take control of the "id"-factor
>
> There must be an easier way.
>
> Thank you.
>
> ______________________________________________
> R-help_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help