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Message-ID: <28521902-45a2-822f-ff70-ca9e44856cb3@gmail.com>
Date: 2019-02-27T21:05:47Z
From: Duncan Murdoch
Subject: Error trapping in R
In-Reply-To: <FD7AB93F-9088-4DA8-A49D-2AB370D27715@comcast.net>

On 27/02/2019 3:55 p.m., Bernard Comcast wrote:
> What is the recommended way to trap errors in R? My main need is to be able to trap an error and then skip a section of code if an error has occurred. In VB for Excel I used the ?On Error goto  .....? construct to do this.

The recommended way is to use tryCatch() around the expression you're 
evaluating.  A simpler, less flexible alternative is try().  The Excel 
version sounds a bit more like try().  You'd use it like this:

   value <- try({ x <- 1
                  y <- someFunction(x)
                  someOtherFunction(y)
                })
   if (inherits(value, "try-error")) {
     cat ("something went wrong.  There's information in value about 
what happened.")
   } else {
     cat ("value is fine, there was no error.")
   }

Duncan Murdoch