R help - Jun 2007 - function with xyplot

Hi,

I'm a new user trying to switch from SAS, so sorry for the beginner's
question: Suppose I have a dataframe DF that contains variables X,Y,Z. I am
trying to write a function like this:

myplot <- function(varname){xyplot(varname ~ Y, group = Z, data = DF)}.

The problem is then how to enter X into my function. If I write
myplot("X")
I get an error because the argument is a string and xyplot can make nothing
out of it. If I write myplot(X) I also get an error that tells me the object
X does not exist.

Thanks for your help,

Diego

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You need to reference the data.frame or append it.  

myplot(DF$X) should work
or 
append(DF)
myplot(X)
--- Diego Gruber <diego.gruber at gmail.com> wrote:
> Hi,
> 
> I'm a new user trying to switch from SAS, so sorry
> for the beginner's
> question: Suppose I have a dataframe DF that
> contains variables X,Y,Z. I am
> trying to write a function like this:
> 
> myplot <- function(varname){xyplot(varname ~ Y,
> group = Z, data = DF)}.
> 
> The problem is then how to enter X into my function.
> If I write myplot("X")
> I get an error because the argument is a string and
> xyplot can make nothing
> out of it. If I write myplot(X) I also get an error
> that tells me the object
> X does not exist.
> 
> Thanks for your help,
> 
> Diego
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained,
> reproducible code.
>

Thanks a lot for your suggestions. Referencing the dataset solved the
problem. I had actually tried it before but since I was also subsetting the
datset within the function (something I didn't mention in my question) the
objects were not of the same length and that caused me trouble. Your comment
made me realize that.

Thanks Hadley for pointing me out to ggplot2, looks like a very complete
graphics package and if it simplifies the programming it must be extremely
useful. I'll make sure to take a closer look at it.

Best regards,

Diego

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