From: Duncan Murdoch <murdoch_at_stats.uwo.ca>

Date: Wed 15 Feb 2006 - 01:50:39 EST

*>
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> Although this does seem to be how xyplot works, I think it indicates

*> there is a problem with it.
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*>
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*> The help file for xyplot indicates that for the xyplot formula method
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*> the default
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*> environment is the caller environment whereas it ought to be the environment
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*> of the formula:
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*>
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*> data: For the 'formula' method, a data frame containing values for
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*> any variables in the formula, as well as 'groups' and
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*> 'subset' if applicable. By default the environment where the
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*> function was called from is used.
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*>
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*> For example, if we replace xyplot with lm it does work as expected:
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*>
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*> fun1 <- function( x=1:5, y=1:5, ... ) fun2( y ~ x, ... )
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*> fun2 <- function( ... ) lm( ... )
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*> fun1()
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R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Feb 15 02:07:45 2006

Date: Wed 15 Feb 2006 - 01:50:39 EST

On 2/14/2006 9:38 AM, Gabor Grothendieck wrote:

> On 2/14/06, Duncan Murdoch <murdoch@stats.uwo.ca> wrote:

>> On 2/14/2006 8:56 AM, Wolfram Fischer wrote: >> > I defined three functions: >> > >> >> fun0 <- function( x=1:5, y=1:5, ... ) xyplot( y ~ x, ... ) >> > >> >> fun1 <- function( x=1:5, y=1:5, ... ) fun2( y ~ x, ... ) >> >> fun2 <- function( ... ) xyplot( ... ) >> > >> > The call of fun0() works as expected. >> > >> > The call of fun1() causes the following error: >> > 'Error in eval(expr, envir, enclos) : object "y" not found' >> > >> > How should I define fun2 to avoid the error? >> >> fun2 is fine, it's fun1 that has problems. It is passing a formula >> through fun2 to xyplot without telling xyplot where to evaluate the >> arguments. If you change it to >> >> fun1 <- function( x=1:5, y=1:5, ... ) fun2( y ~ x, data=enviroment(), ... ) >> >> it will tell xyplot to look in the current environment at the time of >> the call, i.e. the fun1 evaluation environment where x and y live. >>

> Although this does seem to be how xyplot works, I think it indicates

Duncan Murdoch

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Feb 15 02:07:45 2006

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