R help - Jul 2007 - Package manual examples - 'unexpected$undefined' errors

Trying out an unfamiliar package, the natural thing is to use the examples
given in the package's manual - hopefully, the writers of the package
wouldn't include examples which didn't work!

Recently, though, I've been getting 'unexpected$undefined' error
messages
when doing this, despite having copy/pasted the text from the manual (taking
out hard breaks on the way).

Moreover, I've had error messages for commands which I've previously had
work fine.

For instance, this from Zelig

z.out <­ zelig(vote ~ race + educate, model = "logit", data =
turnout)

has at different times worked fine and thrown up the error message.

Any help gratefully received.

	[[alternative HTML version deleted]]

Trying out an unfamiliar package, the natural thing is to use the examples
given in the package's manual - hopefully, the writers of the package
wouldn't include examples which didn't work!

Recently, though, I've been getting 'unexpected$undefined' error
messages
when doing this, despite having copy/pasted the text from the manual (taking
out hard breaks on the way).

Moreover, I've had error messages for commands which I've previously had
work fine.

For instance, this from Zelig

z.out <­ zelig(vote ~ race + educate, model = "logit", data =
turnout)

has at different times worked fine and thrown up the error message.

Any help gratefully received.

	[[alternative HTML version deleted]]

Bounced first time!

---------- Forwarded message ----------
From: David Pain <dsp0718 at googlemail.com>
Date: 28-Jul-2007 11:03
Subject: Package manual examples - 'unexpected$undefined' errors
To: r-help at stat.math.ethz.ch


Trying out an unfamiliar package, the natural thing is to use the
examples given in the package's manual - hopefully, the writers of the
package wouldn't include examples which didn't work!

Recently, though, I've been getting 'unexpected$undefined' error
messages when doing this, despite having copy/pasted the text from the
manual (taking out hard breaks on the way).

Moreover, I've had error messages for commands which I've previously
had work fine.

For instance, this from Zelig

z.out <? zelig(vote ~ race + educate, model = "logit", data =
turnout)

has at different times worked fine and thrown up the error message.

Any help gratefully received.

David Pain wrote:
> Trying out an unfamiliar package, the natural thing is to use the examples
> given in the package's manual - hopefully, the writers of the package
> wouldn't include examples which didn't work!
>
> Recently, though, I've been getting 'unexpected$undefined'
error messages
> when doing this, despite having copy/pasted the text from the manual
(taking
> out hard breaks on the way).
>
> Moreover, I've had error messages for commands which I've
previously had
> work fine.
>
> For instance, this from Zelig
>
> z.out <? zelig(vote ~ race + educate, model = "logit", data =
turnout)
>
> has at different times worked fine and thrown up the error message.
>
> Any help gratefully received.
>
> 	[[alternative HTML version deleted]]
It's hard to say exactly what's going wrong, but a guess is that in your
workspace you have an object which is somehow conflicting with an object 
in the package.  Try starting R with the --vanilla command line option
and if the errors go away, that's why.

I don't know whether this applies to the Zelig package, but packages 
that don't define namespaces are fragile in that their internal 
functions can be masked by same-named functions in your workspace.  Even 
if the package does have a namespace, you can mask functions from it 
that you call:  for example, if you had a function called zelig (perhaps 
because you used fix(zelig) to make a small change to the existing one), 
your line above would call yours, not the original.

Duncan Murdoch