function in order to plot the same graph to postscript and pdf

Use substitute() instead of expression(); choose to use either MYPLOT or
myplot because they are different variables; and use parentheses around
your function arguments instead of braces.

-----Original Message-----
From: Ronny Klein [mailto:ronny.klein at wiwi.uni-halle.de] 
Sent: Wednesday, March 09, 2005 12:22 PM
To: Achim Zeileis
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] function in order to plot the same graph to postscript
and pdf

The myplot is something like this:

plot(x)
text(foo)

Aha, I was surprised that this worked for one of the two plots.
You could pass myplot as an expression, e.g. myplot =
expression(plot(x)), and then eval() that in the body of plot.both().

I've followed your advice and changed my function to something like
this:

plot.both <- function{myplot, filename}{
     MYPLOT <- expression(myplot)
     pdf(file=paste(filename, ".pdf", sep=""))
     eval(myplot)
     dev.off()
     postscript(file=paste(filename, ".eps", sep=""))
     eval(myplot)
    dev.off()
 }

However the result is the same: the first one is actually printed but
the 
second plot is empty. 

Ronny

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