On Aug 26, 2010, at 9:07 PM, pdb wrote:
Hi,
I am writing a function that requires a specific package to be
installed.
Is there a way of checking if the package is installed and returning
a TRUE
/ FALSE result so my function can return an appropriate error
message and
exit the function gracefully rather than just bombing out?
I'm thinking along the following lines (but want code that works),
f_checkpackage <- function()
{
if (library(madeupname) == TRUE) {
You don't need the ==TRUE
> if ( require(rms) ) {TRUE}
[1] TRUE
> if ( require(beanplot) ) {TRUE} else {FALSE}
Loading required package: beanplot
[1] FALSE
Warning message:
In library(package, lib.loc = lib.loc, character.only = TRUE,
logical.return = TRUE, :
there is no package called 'beanplot'
According to the library/require help page library can be cajoled into
returning a logical vlaue if you tell it: logical.return = TRUE
.
--
David.
cat("package loaded OK\n")
}
else
{
cat("ERROR: package not loaded")
}
}
f_checkpackage()
--
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David Winsemius, MD
West Hartford, CT
______________________________________________
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