R help - Dec 2010 - How to suppress plotting for "xyplot(zoo(x))"?

Hi,

I found the thread
http://r.789695.n4.nabble.com/Matrix-as-input-to-xyplot-lattice-proper-extended-formula-syntax-td896948.html
I used Gabor's approach and then tried to assign the plot to a variable (see
below). But a Quartz device is opened... why? I don't want to have anything
plot/printed, I just would like to store the plot object. Is there something
like "plot = FALSE"?

Cheers,

Marius

library(lattice)
library(zoo)

df <- data.frame(y = matrix(rnorm(24), nrow = 6), x = 1:6) 
xyplot(zoo(df[1:4], df$x), type = "p")

plot.object <- xyplot(zoo(df[1:4], df$x), type = "p") # problem: a
Quartz device is opened (on Mac OS X 10.6)

On Tue, Dec 21, 2010 at 7:53 AM, Marius Hofert <m_hofert at web.de>
wrote:
> Hi,
>
> I found the thread
http://r.789695.n4.nabble.com/Matrix-as-input-to-xyplot-lattice-proper-extended-formula-syntax-td896948.html
> I used Gabor's approach and then tried to assign the plot to a variable
(see below). But a Quartz device is opened... why? I don't want to have
anything plot/printed, I just would like to store the plot object. Is there
something like "plot = FALSE"?
>
> Cheers,
>
> Marius
>
> library(lattice)
> library(zoo)
>
> df <- data.frame(y = matrix(rnorm(24), nrow = 6), x = 1:6)
> xyplot(zoo(df[1:4], df$x), type = "p")
>
> plot.object <- xyplot(zoo(df[1:4], df$x), type = "p") #
problem: a Quartz device is opened (on Mac OS X 10.6)
This also opens up a window on Windows.   It occurs within lattice
when lattice issues a trellis.par.get .  A workaround would be to open
a device directed to null.  On Windows this would work.  I assume if
you use "/dev/null" it would work on your machine.

png("NUL")
plot.object <- ...
dev.off()





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