On 20/05/2016 10:33 AM, William Dunlap wrote:
The following usage of stopifnot seems reasonable to me and it would be nice if the 2nd call caused the message 'is.data.frame(df) is not TRUE'.f <- function(df) { stopifnot(is.data.frame(df), is.integer(df$ID)) range(df$ID) }
Yes, that's an example where the proposed behaviour makes sense. But stopifnot(is.data.frame(df)); stopifnot(is.integer(df$ID)) isn't that much harder to type, and it already does what you want. Duncan Murdoch
f(data.frame(ID=4:7)) # [1] 4 7 f(4:7) # Error in df$ID : $ operator is invalid for atomic vectors Bill Dunlap TIBCO Software wdunlap tibco.com <http://tibco.com> On Fri, May 20, 2016 at 7:13 AM, Duncan Murdoch <murdoch.dun...@gmail.com <mailto:murdoch.dun...@gmail.com>> wrote: On 20/05/2016 4:44 AM, Vasanth Mohan wrote: Hi, *stopifnot(FALSE, someOtherExpression)* For the above code I expect stopifnot() to always say that 'FALSE is not TRUE' regardless of what someOtherExpression is(It may evaluate to TRUE or FALSE or throw an error). Is my expectation correct? Is that how stopifnot() is supposed to work? The present implementation of stopifnot() does not work like that. If someOtherExpression would throw an error, then stopifnot() throws that error instead of saying 'FALSE is not TRUE'. So, I modified the source code of stopifnot() and now it works as I expect it to. If that is how stopifnot() is supposed to work, then kindly let me know how I can contribute my solution The documentation is unclear on that. First it implies all expressions are evaluated: "If any of the expressions in ... are not all TRUE, stop is called, producing an error message indicating the first of the elements of ... which were not true." But then the "conceptually equivalent" code acts the way you expected. However, it doesn't really make sense to me to put in tests that could themselves trigger errors unless you'd be interested in seeing those errors, so I don't think I'd change it. Duncan Murdoch ______________________________________________ R-help@r-project.org <mailto:R-help@r-project.org> mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
