[R] Using bquote: question

Bert Gunter gunter.berton at gene.com
Fri Jan 25 04:54:10 CET 2008

I should have perhaps phrased my previous post better as: the result of
bquote() is a language expression argument of mode "call" which gets
evaluated by the plotmath functionality in your first plot call, but  gets
evaluated in the global environment in the second before being passed back
to the plot.default method that will be called by plot.formula to do the

-- Bert Gunter

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
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Sent: Thursday, January 24, 2008 5:58 PM
To: R-help mailing list
Subject: [R] Using bquote: question

Hi all


x <- c(1,2)
y <- c(1,-1)

phi <- 1
p <- 2

par( mfrow=c(1,2))
plot(x , y, main=bquote( paste( p==.(p)," and ",phi==.(phi)) ) )
plot(y ~ x, main=bquote( paste( p==.(p)," and ",phi==.(phi)) ) )
par( mfrow=c(1,2))

On my system (details below), the first plot is correct (in my 
understanding), and produces a title reading "p=2 and phi=1" (with 
appropriate Greek for phi).

However, the second produces the title "TRUE and TRUE".

Is this a bug, or a misunderstanding or my part(in which case, I'm 
sure I'll be told the obscure location where this is documented!)?



> sessionInfo()
R version 2.6.0 (2007-10-03)


attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] tweedie_1.5.3 statmod_1.3.0

loaded via a namespace (and not attached):
[1] rcompgen_0.1-15

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