R help - Aug 2010 - xyplot plot with groups

Hi, I am a beginner of xyplot() (or lattice package). On one hand, I immediately
realized it's a very powerful utility. On the other hand, there are too many
things for me to learn. Still haven't figure out a generalization of the
syntax
and usage under many different circumstances.

Let me give an example dataset:


xxx<-cbind(expand.grid(day=0:7,trt=c('A','B','C'),sex=c('M','F')),subject=rep(1:60,each=8))

xxx<-xxx[sort.list(xxx$trt),]
y<-c(rnorm(160,15),rnorm(160,10),rnorm(160,5))

dat<-cbind(y=y,xxx)

str(dat)
'data.frame':   480 obs. of  5 variables:
 $ y      : num  13.4 15.3 14.4 16.2 15.1 ...
 $ day    : int  0 1 2 3 4 5 6 7 0 1 ...
 $ trt    : Factor w/ 3 levels "A","B","C": 1 1 1
1 1 1 1 1 1 1 ...
 $ sex    : Factor w/ 2 levels "M","F": 1 1 1 1 1 1 1 1 2 2
...
 $ subject: int  1 1 1 1 1 1 1 1 4 4 ...

So this is a typical longitudinal dataset: each subject has measurements for 8 
days (0 to 7), there are 3 treatments (A, B and C), and sex factor (M and F). I 
would like to have 2 plots, one for each sex. Within each plot, I want to plot 3
averaged lines (average of y for each day), one for each treatment group. How 
can I do this?

I tried the following using panel.average(), but it seems that the groups 
information was not passed automatically to panel.average(). 


xyplot(y~day|sex, groups=trt, data=dat, type=c('p','g'),
panel=function(...)
{panel.xyplot(...); panel.average(..., fun=function(x) 
mean(x,na.rm=T),horizontal=F,col=1:3)})

Appreciate if anyone can help.

John

Hi:

Like this?

xyplot(y~day|sex, groups=trt, data=dat, type=c('p','g',
'a'))

The 'a' stands for average line, or 'connect the averages at
different x
values'.
By using the groups = trt argument, you get one line per treatment group in
each panel.

A complete list of valid types is given on p. 75 of the Lattice book
(Sarkar, 2008).
Related types are:
     'l' : join points by lines
     'r': least squares line
     'smooth': loess smooth

HTH,
Dennis

On Fri, Aug 20, 2010 at 3:07 PM, array chip <arrayprofile@yahoo.com>
wrote:
> Hi, I am a beginner of xyplot() (or lattice package). On one hand, I
> immediately
> realized it's a very powerful utility. On the other hand, there are too
> many
> things for me to learn. Still haven't figure out a generalization of
the
> syntax
> and usage under many different circumstances.
>
> Let me give an example dataset:
>
>
>
>
xxx<-cbind(expand.grid(day=0:7,trt=c('A','B','C'),sex=c('M','F')),subject=rep(1:60,each=8))
>
> xxx<-xxx[sort.list(xxx$trt),]
> y<-c(rnorm(160,15),rnorm(160,10),rnorm(160,5))
>
> dat<-cbind(y=y,xxx)
>
> str(dat)
> 'data.frame':   480 obs. of  5 variables:
>  $ y      : num  13.4 15.3 14.4 16.2 15.1 ...
>  $ day    : int  0 1 2 3 4 5 6 7 0 1 ...
>  $ trt    : Factor w/ 3 levels "A","B","C": 1
1 1 1 1 1 1 1 1 1 ...
>  $ sex    : Factor w/ 2 levels "M","F": 1 1 1 1 1 1 1 1
2 2 ...
>  $ subject: int  1 1 1 1 1 1 1 1 4 4 ...
>
> So this is a typical longitudinal dataset: each subject has measurements
> for 8
> days (0 to 7), there are 3 treatments (A, B and C), and sex factor (M and
> F). I
> would like to have 2 plots, one for each sex. Within each plot, I want to
> plot 3
> averaged lines (average of y for each day), one for each treatment group.
> How
> can I do this?
>
> I tried the following using panel.average(), but it seems that the groups
> information was not passed automatically to panel.average().
>
>
> xyplot(y~day|sex, groups=trt, data=dat, type=c('p','g'),
> panel=function(...)
> {panel.xyplot(...); panel.average(..., fun=function(x)
> mean(x,na.rm=T),horizontal=F,col=1:3)})
>
> Appreciate if anyone can help.
>
> John
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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