R help - Apr 2012 - determining if a function exists in a particular package

Hello R People:

Is there a way to determine if a function exists in a particular
package, please?

I looked at exists and objects, but they seem to refer to an
environment rather than a package.

I was thinking of something like:

ifelse(exists(functiona) in MASS, print(1:10), print(5))

Thanks,
Erin


-- 
Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com

I found the solution in an old post:

It's
lsf.str("package:ts")

for functions.

Cool!

On Fri, Apr 27, 2012 at 4:12 PM, Mark Leeds <markleeds2 at gmail.com>
wrote:
> Hi Erin: I don't know how to do it programatically but it might be
quicker
> to just
> go to the vignette and click on it. All the functions should be in the
right
> column of
> the pdf. Of course, you may have reason for needing it programatically in
> which
> case, my apologies for the noise !!!!!
>
> On Fri, Apr 27, 2012 at 5:07 PM, Erin Hodgess <erinm.hodgess at
gmail.com>
> wrote:
>>
>> Hello R People:
>>
>> Is there a way to determine if a function exists in a particular
>> package, please?
>>
>> I looked at exists and objects, but they seem to refer to an
>> environment rather than a package.
>>
>> I was thinking of something like:
>>
>> ifelse(exists(functiona) in MASS, print(1:10), print(5))
>>
>> Thanks,
>> Erin
>>
>>
>> --
>> Erin Hodgess
>> Associate Professor
>> Department of Computer and Mathematical Sciences
>> University of Houston - Downtown
>> mailto: erinm.hodgess at gmail.com
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>


-- 
Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com

> I looked at exists and objects, but they seem to refer to an
> environment rather than a package.
Those functions work with the names of attached packages, but you have
know that the name of an attached package has "package:" prefixed to
the package's usual name.  E.g.,
  > exists("lm", "package:stats")
  [1] TRUE
  > objects("package:stats", pattern="iso")
  [1] "isoreg"
If you leave off the "package:" you might be misled into thinking an
environment is required:
  > objects("stats", pattern="iso")
  Error in as.environment(pos) : no item called "stats" on the search
list

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org] On Behalf
> Of Erin Hodgess
> Sent: Friday, April 27, 2012 2:08 PM
> To: R help
> Subject: [R] determining if a function exists in a particular package
> 
> Hello R People:
> 
> Is there a way to determine if a function exists in a particular
> package, please?
> 
> I looked at exists and objects, but they seem to refer to an
> environment rather than a package.
> 
> I was thinking of something like:
> 
> ifelse(exists(functiona) in MASS, print(1:10), print(5))
> 
> Thanks,
> Erin
> 
> 
> --
> Erin Hodgess
> Associate Professor
> Department of Computer and Mathematical Sciences
> University of Houston - Downtown
> mailto: erinm.hodgess at gmail.com
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.