R help - Mar 2008 - When to quote a package name

Dear HelpeRs,

I'm confused about the role of quotes around package names on the
library and detach functions. Books on R use both approaches:

library(Hmisc)
describe(mydata)
detach(package:Hmisc)

and

library("Hmisc")
describe(mydata)
detach("package:Hmisc")

The help file for detach says "quoted or unquoted" and the help file
for
library says about the package, "the name of a package, given as a name
or literal character string, or a character string, depending on whether
character.only is FALSE (default) or TRUE)."

Are there conditions under which it matters? Which is best?

Thanks,
Bob

========================================================Bob Muenchen (pronounced
Min'-chen),
Manager, Statistical Consulting Center 
U of TN Office of Information Technology
Stokely Management Center, Suite 200
916 Volunteer Blvd., Knoxville, TN 37996-0520
Voice: (865) 974-5230
FAX: (865) 974-4810
Email: muenchen at utk.edu
Web: http://oit.utk.edu/scc
Map: http://www.utk.edu/maps 
News: http://listserv.utk.edu/archives/statnews.html
=========================================================

Muenchen, Robert A (Bob) wrote:
> Dear HelpeRs,
> 
> I'm confused about the role of quotes around package names on the
> library and detach functions. Books on R use both approaches:
> 
> library(Hmisc)
> describe(mydata)
> detach(package:Hmisc)
> 
> and
> 
> library("Hmisc")
> describe(mydata)
> detach("package:Hmisc")
> 
> The help file for detach says "quoted or unquoted" and the help
file for
> library says about the package, "the name of a package, given as a
name
> or literal character string, or a character string, depending on whether
> character.only is FALSE (default) or TRUE)."
> 
> Are there conditions under which it matters? Which is best?
> 
The cleaner approach is to use quotes. I'd expect

x <- "Hmisc"
library(x)

to install package "Hmisc", but not package "x"...
In fact, it also installs "x" (as documented), unfortunately.

Uwe Ligges


> Thanks,
> Bob
> 
> ========================================================> Bob Muenchen
(pronounced Min'-chen),
> Manager, Statistical Consulting Center 
> U of TN Office of Information Technology
> Stokely Management Center, Suite 200
> 916 Volunteer Blvd., Knoxville, TN 37996-0520
> Voice: (865) 974-5230
> FAX: (865) 974-4810
> Email: muenchen at utk.edu
> Web: http://oit.utk.edu/scc
> Map: http://www.utk.edu/maps 
> News: http://listserv.utk.edu/archives/statnews.html
> ========================================================> 
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