Is there a way to test if a library has been loaded? is.loaded does not give me what I want, I am looking to say: if loaded(Rdbi) dbSendQuery(conn, q) if loaded(RODBC) sqlQuery(conn, q) I need this to support both unix and windows platforms as I could not find a windows distribution for RdbiPgSQL. I am using R 2.1.0 and postgresql. I will be connecting to the database using Rdbi and RdbiPgSQL and have other developers using windows connect with RODBC, unless someone can suggest a better solution.
On 9/13/2005 3:09 PM, Omar Lakkis wrote:> Is there a way to test if a library has been loaded? > > is.loaded does not give me what I want, I am looking to say: > > if loaded(Rdbi) dbSendQuery(conn, q) > if loaded(RODBC) sqlQuery(conn, q) > > I need this to support both unix and windows platforms as I could not > find a windows distribution for RdbiPgSQL. I am using R 2.1.0 and > postgresql. I will be connecting to the database using Rdbi and > RdbiPgSQL and have other developers using windows connect with RODBC, > unless someone can suggest a better solution.You can use the strangely named "require" function, as in if (require(Rdbi)) dbSendQuery(conn, q) else if (require(RODBC) sqlQuery(conn, q) else stop("Nothing works") Duncan Murdoch
Dear Omar,
The following function tests whether a package is in the search path (with
the package name given in quotes):
packageLoaded <- function(name) 0 != length(grep(paste("^package:",
name,
"$", sep=""), search()))
I hope this helps,
John
--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox
--------------------------------
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Omar Lakkis
> Sent: Tuesday, September 13, 2005 2:09 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] is library loaded
>
> Is there a way to test if a library has been loaded?
>
> is.loaded does not give me what I want, I am looking to say:
>
> if loaded(Rdbi) dbSendQuery(conn, q)
> if loaded(RODBC) sqlQuery(conn, q)
>
> I need this to support both unix and windows platforms as I
> could not find a windows distribution for RdbiPgSQL. I am
> using R 2.1.0 and postgresql. I will be connecting to the
> database using Rdbi and RdbiPgSQL and have other developers
> using windows connect with RODBC, unless someone can suggest
> a better solution.
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
Hi,
Almost surely this is a bad name. With the advent of name spaces it is
important to distinguish between loading and attaching. This function
tests for attached packages. To test for loaded packages we already have
loadedNamespaces.
Best wishes,
Robert
John Fox wrote:> Dear Omar,
>
> The following function tests whether a package is in the search path (with
> the package name given in quotes):
>
> packageLoaded <- function(name) 0 !=
length(grep(paste("^package:", name,
> "$", sep=""), search()))
>
> I hope this helps,
> John
>
> --------------------------------
> John Fox
> Department of Sociology
> McMaster University
> Hamilton, Ontario
> Canada L8S 4M4
> 905-525-9140x23604
> http://socserv.mcmaster.ca/jfox
> --------------------------------
>
>
>>-----Original Message-----
>>From: r-help-bounces at stat.math.ethz.ch
>>[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Omar Lakkis
>>Sent: Tuesday, September 13, 2005 2:09 PM
>>To: r-help at stat.math.ethz.ch
>>Subject: [R] is library loaded
>>
>>Is there a way to test if a library has been loaded?
>>
>>is.loaded does not give me what I want, I am looking to say:
>>
>>if loaded(Rdbi) dbSendQuery(conn, q)
>>if loaded(RODBC) sqlQuery(conn, q)
>>
>>I need this to support both unix and windows platforms as I
>>could not find a windows distribution for RdbiPgSQL. I am
>>using R 2.1.0 and postgresql. I will be connecting to the
>>database using Rdbi and RdbiPgSQL and have other developers
>>using windows connect with RODBC, unless someone can suggest
>>a better solution.
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide!
>>http://www.R-project.org/posting-guide.html
>
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
--
Robert Gentleman, PhD
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M2-B876
PO Box 19024
Seattle, Washington 98109-1024
206-667-7700
rgentlem at fhcrc.org