Hi all,
Tinkering with a wrapper for xyplot that will help me plot a bunch of
plots in a data analysis I'm doing and I ran into an odd error that
I'm guessing is a scope issue. Here's a very simple version of the code:
###############
#load lattice
library(lattice)
#create the wrapper function
do.xyplot = function( plot.formula, data.frame, plot.groups){
print(plot.groups) #show me what the wrapper function thinks
'plot.groups' is
xyplot(
plot.formula
,data = data.frame
,groups = eval(plot.groups)
)
}
#create some data
mydata = as.data.frame(cbind( x = c(1:4), y = rep(1:2), z = rep(1:2,
each = 2) ))
#try to plot the data (fails)
do.xyplot(
plot.formula=formula(x~y)
,data.frame = mydata
,plot.groups = expression(z)
)
#after error message try again, this time declaring plot.groups as a
global variable (succeeds)
plot.groups = expression(z)
do.xyplot(
plot.formula=formula(x~y)
,data.frame = mydata
,plot.groups = expression(z)
)
#############
I'm fine with declaring plot.groups before each call to do.xyplot,
but I'm curious if there's a simpler solution.
Mike
--
Mike Lawrence
Graduate Student, Department of Psychology, Dalhousie University
Website: http://memetic.ca
Public calendar: http://icalx.com/public/informavore/Public
"The road to wisdom? Well, it's plain and simple to express:
Err and err and err again, but less and less and less."
- Piet Hein
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