[R] stuck on making a line graph across time, with 4 categories

[Ben Bolker]

Christopher W. Ryan <cryan <at> binghamton.edu> writes:

> 
> I can't seem to find just what I'm looking for in R help, Everitt and
> Hothorn HSAUR, Murrell's book, or the R graphics gallery at
> http://addictedtor.free.fr/graphiques/.  Probably not looking
> efficiently, but anyway,
> 
> If my data look like this:
> 
> > head(data)
>       cat startyear studentid
> 1   other      2001        12
> 2     UHS      2001        17
> 3 Lourdes      2001        10
> 4 Endwell      2001         3
> 5   other      2002        13
> 6     UHS      2002        19
> >
> 
> What is the easiest way to make a line graph like this (made this one in
> Stata):
> 
> http://bingweb.binghamton.edu/~cryan/Workload.png
> 
> Thank you.

  assuming "studentid" is your students,

library(lattice)
xyplot(studentid~startyear,groups=cat,auto.key=TRUE,type="l",data=data)

  (I think -- haven't tested at all)
  that, or reshape the data to wide format and use matplot.

  Ben Bolker