how to check if a library is loaded, from a function
On Jan 31, 2011, at 11:04 PM, Nick Matzke wrote:
Hi, I've written a function which I load with a source command. The function requires a certain library, phangorn, to work. I would like the function to check if phangorn is loaded as a library before running. For some reason, just putting require(phangorn) into the sourced function doesn't do anything.
If a package is already loaded then require() will not load it again. I think it is also going to be quiet if it's called in a sourced routine, so I would ask whether you have properly tested your claim that it "doesn't do anything"? If you start with a clean session and source your routine, does the routine fail because the package does not load?
This must be simple, but I can't figure it out! Any help appreciated... -- ==================================================== Nicholas J. Matzke Ph.D. Candidate, Graduate Student Researcher
30 line sig elided.
David Winsemius, MD West Hartford, CT