Dear Henrik, Simon, and Adrian, As it turns out Adrian's admisc::tryCatchWEM() *almost* does what I want, which is both to capture all messages and the result of the expression (rather than the visible representation of the result). I was easily able to modify tryCatchWEM() to return the result.
Henrik: I was aware that tryCatch() doesn't return the final result of the expression, and I was previously re-executing the expression to capture the reult, but only getting the first warning message, along with the result. Thanks for responding to my question and providing viable solutions, John On 2021-12-02, 5:19 PM, "Henrik Bengtsson" <[email protected]> wrote: Simon's suggestion with withCallingHandlers() is the correct way. Also, note that if you use tryCatch() to catch warnings, you're *interrupting* the evaluation of the expression of interest, e.g. > res <- tryCatch({ message("hey"); warning("boom"); message("there"); 42 }, warning = function(w) { message("Warning caught: ", conditionMessage(w)); 3.14 }) hey Warning caught: boom > res [1] 3.14 Note how it never completes your expression. /Henrik On Thu, Dec 2, 2021 at 1:14 PM Simon Urbanek <[email protected]> wrote: > > > Adapted from demo(error.catching): > > > W=list() > > withCallingHandlers(foo(), warning=function(w) { W <<- c(W, list(w)); invokeRestart("muffleWarning") }) > > str(W) > List of 2 > $ :List of 2 > ..$ message: chr "warning 1" > ..$ call : language foo() > ..- attr(*, "class")= chr [1:3] "simpleWarning" "warning" "condition" > $ :List of 2 > ..$ message: chr "warning 2" > ..$ call : language foo() > ..- attr(*, "class")= chr [1:3] "simpleWarning" "warning" "condition" > > Cheers, > Simon > > > > On Dec 3, 2021, at 10:02 AM, Fox, John <[email protected]> wrote: > > > > Dear R-devel list members, > > > > Is it possible to capture more than one warning message using tryCatch()? The answer may be in ?conditions, but, if it is, I can't locate it. > > > > For example, in the following only the first warning message is captured and reported: > > > >> foo <- function(){ > > + warning("warning 1") > > + warning("warning 2") > > + } > > > >> foo() > > Warning messages: > > 1: In foo() : warning 1 > > 2: In foo() : warning 2 > > > >> bar <- function(){ > > + tryCatch(foo(), warning=function(w) print(w)) > > + } > > > >> bar() > > <simpleWarning in foo(): warning 1> > > > > Is there a way to capture "warning 2" as well? > > > > Any help would be appreciated. > > > > John > > > > -- > > John Fox, Professor Emeritus > > McMaster University > > Hamilton, Ontario, Canada > > Web: http://socserv.mcmaster.ca/jfox/ > > > > > > > > ______________________________________________ > > [email protected] mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
