R help - Oct 2013 - How to extract the error flag from 'try'

Hello!

I need to flag my operation as an error if it produces an error.

For example, this expression produces an error:
test<-try(log("a"))
str(test)

However, how can I proceed using the information contained in test object?
I am looking for something like:
if test is an error {do this and this}
But I am not sure how to do it.

I tried:

class(test) %in% "try_error"

But it says: FALSE

Thank you very much!

-- 
Dimitri Liakhovitski

	[[alternative HTML version deleted]]

On Thu, Oct 3, 2013 at 8:57 AM, Dimitri Liakhovitski
<dimitri.liakhovitski at gmail.com> wrote:
> Hello!
>
> I need to flag my operation as an error if it produces an error.
>
> For example, this expression produces an error:
> test<-try(log("a"))
> str(test)
>
> However, how can I proceed using the information contained in test object?
> I am looking for something like:
> if test is an error {do this and this}
> But I am not sure how to do it.
>
> I tried:
>
> class(test) %in% "try_error"
>
Try this code:
> res <- try(log("a"))
Error in log("a") : non-numeric argument to mathematical
function
> if (inherits(res, "try-error")) cat(attr(res,
"condition")$message, "\n")
non-numeric argument to mathematical function

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