[R] Difficulty using the tryCatch() function

[Jeff Newmiller]

Too many curly braces. warning and error need to be arguments to tryCatch.

On February 7, 2021 11:30:59 AM PST, phil using philipsmith.ca wrote:
>I need help using the tryCatch function. I have a function and I want
>to 
>surround it with tryCatch to catch errors and thereby avoid stopping 
>execution of my program if the function fails. In my reproducible 
>example below I have used a very simply function that just adds two 
>numbers together. My function, called Adn, compiles, but when executed 
>it generates the message: "Error in tryCatch({ : condition handlers
>must 
>be specified with a condition class". I do not understand the error 
>message.
>
># Reproducible example for using tryCatch
>
>Adn <- function(x,y) {
>   out <- tryCatch(
>     {
>       x+y
>     },
>     {
>       warning = function(cond) {
>         message("There was a warning.")
>         message("Here is the original warning message:")
>         message(cond)
>         return(100)
>       }
>     },
>     {
>       error = function(cond) {
>         message("There was an error.")
>         message("Here is the original error message:")
>         message(cond)
>         return(200)
>       }
>     },
>     finally = {
>       message("Error handling done.")
>     }
>   )
>   if (out==100 | out==200) { z <- 0 }
>   else { z <- x+y }
>   return(z)
>}
>(result <- Adn(1,sqrt(2))) # should work fine
>(result <- Adn(1,sqrt(-2))) # should catch a warning and set z to 0
>(result <- Adn(1,"a")) # should catch an error and set z to 0
>
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-- 
Sent from my phone. Please excuse my brevity.