R help - May 2007 - Barplot by two variables

Hi all
I have a bit of a problem.  I want to make a barplot of some data.  My
data is of a score that is separated by year and by a limit (above 3 and
below 3 to calculate the score).
Year	Limit	HSS
1999	ALT	0.675
1999	VFR	0.521	
2000	ALT	0.264
2000	VFR	0.295

I would like to have a barplot with year on the x axis and HSS on the y
axis and the two limits as two different colors to show the difference.
Using (dataset$HSS, col=c("green","purple"))  I  get some of
the plot
but I don't know how to get labels on the bottom for each year and I
can't get a legend for my barplot.  Not really sure what I am doing
wrong but any help would be much appreciated.  

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On 5/10/07, Spilak,Jacqueline [Edm] <Jacqueline.Spilak at ec.gc.ca>
wrote:
> Hi all
> I have a bit of a problem.  I want to make a barplot of some data.  My
> data is of a score that is separated by year and by a limit (above 3 and
> below 3 to calculate the score).
> Year    Limit   HSS
> 1999    ALT     0.675
> 1999    VFR     0.521
> 2000    ALT     0.264
> 2000    VFR     0.295
>
> I would like to have a barplot with year on the x axis and HSS on the y
> axis and the two limits as two different colors to show the difference.
> Using (dataset$HSS, col=c("green","purple"))  I  get
some of the plot
> but I don't know how to get labels on the bottom for each year and I
> can't get a legend for my barplot.  Not really sure what I am doing
> wrong but any help would be much appreciated.
Here's one solution using the lattice package:

library(lattice)
barchart(HSS ~ factor(Year), data = dataset, origin = 0,
         groups = Limit, auto.key = TRUE)

-Deepayan