Message-ID: <856018ED-E530-44EC-A1D2-75DBC51975EA@kasterma.net>
Date: 2014-08-22T11:35:41Z
From: Bart Kastermans
Subject: knitr and stopifnot replacement.
In-Reply-To: <53F71DFB.60909@gmail.com>
On 22 Aug 2014, at 12:39, Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
> On 22/08/2014, 6:02 AM, Bart Kastermans wrote:
>> I have a daily generated report in which I put a check using stopifnot. Unfortunately
>> I didn?t check the effect very well, turns out that if the condition checked fails
>> this is not shown in the knitr output (I only get an error much later due to a missing
>> object).
>>
>> So my question is, what is the correct way to use assertions in a <filename>.Rnw
>> file. I want to perform a check, and if it fails everything should stop with a message
>> I can generate.
>>
>
> One of the differences between knitr and Sweave is that knitr handles
> errors, and Sweave doesn't. I expect there's some knitr option to tell
> it to quit in case of error (a hook?), but you'll have to check the
> documentation to find it.
Thanks; that helped me to find the exact right option:
<<filelist, error=FALSE>>=
# check all files exist before continuing
stopifnot(all(sapply(files, file.exists)))
@
>
> Duncan Murdoch
>