Hello,
I remembered having seen a function tryCatch.W.E and after an online
search, found where.
It was in a R-Help post and in demo(error.catching). The question by
Marius Hofert [1] was answered, among others, by Martin Maechler [2]
which included the function tryCatch.W.E.
These posts refer to an old thread dated 2004 [3], with an answer by
Luke Tierney [4]. The function withWarnings posted by Luke returns all
warning messages in a list, as seen below.
I repost the function to have this self contained.
withWarnings <- function (expr) {
warnings <- character()
retval <- withCallingHandlers(expr, warning = function(ex) {
warnings <<- c(warnings, conditionMessage(ex))
invokeRestart("muffleWarning")
})
list(Value = retval, Warnings = warnings)
}
withWarnings(foo())
#$Value
#[1] "warning 2"
#
#$Warnings
#[1] "warning 1" "warning 2"
Function tryCatch.W.E is now part of contributed package simsalapar [5],
with credits to Marius and Martin given in its documentation.
[1] https://stat.ethz.ch/pipermail/r-help/2010-December/262185.html
[2] https://stat.ethz.ch/pipermail/r-help/2010-December/262626.html
[3] https://stat.ethz.ch/pipermail/r-help/2004-June/052092.html
[4] https://stat.ethz.ch/pipermail/r-help/2004-June/052132.html
[5] https://CRAN.R-project.org/package=simsalapar
Hope this helps,
Rui Barradas
Às 22:37 de 02/12/21, Fox, John escreveu:
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" <henrik.bengts...@gmail.com> 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
<simon.urba...@r-project.org> 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 <j...@mcmaster.ca> 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/
> >
> >
> >
> > ______________________________________________
> > R-devel@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
> >
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
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