Exception handling in R

Question

Does anyone have examples/tutorials of exception handling in R? The official documentation is very terse.

Answer 1

Basically you want to use the tryCatch() function. Look at help("tryCatch") for more details.

Here's a trivial example (keep in mind that you can do whatever you want with an error):

vari <- 1
tryCatch(print("passes"), error = function(e) print(vari), finally=print("finished")) 
tryCatch(stop("fails"), error = function(e) print(vari), finally=print("finished")) 

Have a look at these related questions:

• http://stackoverflow.com/questions/1608130/equivalent-of-throw-in-r
• http://stackoverflow.com/questions/2158780/r-catching-an-error-and-then-branching-logic
• http://stackoverflow.com/search?q=[r]+trycatch

Answer 2

Besides Shane's answer pointing you to other StackOverflow discussions, you could try Google Code Search as e.g. in this query for tryCatch in language=R.

Just for the record, there is also try but tryCatch may be preferable. I tried a quick count at Google Code Search but try gets too many false positives for the verb itself -- yet it seems tryCatch is more widely used.