Joris Meys
2017-May-23 15:53 UTC
[Rd] Inconsistency in handling of numeric input with %d by sprintf
I initially thought this is "documented behaviour". ?sprintf says: Numeric variables with __exactly integer__ values will be coerced to integer. (emphasis mine). Turns out this only works when the first value is numeric and not NA, as shown by the following example:> sprintf("%d", as.numeric(c(NA,1)))Error in sprintf("%d", as.numeric(c(NA, 1))) : invalid format '%d'; use format %f, %e, %g or %a for numeric objects> sprintf("%d", as.numeric(c(1,NA)))[1] "1" "NA" So the safest thing is indeed passing the right type, but the behaviour is indeed confusing. I checked this on both Windows and Debian, and on both systems I get the exact same response. Cheers Joris On Tue, May 23, 2017 at 4:53 PM, Evan Cortens <ecortens at mtroyal.ca> wrote:> Hi Michael, > > I posted something on this topic to R-devel several weeks ago, but never > got a response. My ultimate conclusion is that sprintf() isn't super > consistent in how it handles coercion: sometimes it'll coerce real to > integer without complaint, other times it won't. (My particular email had > to do with the vectors longer than 1 and their positioning vis-a-vis the > format string.) The safest thing is just to pass the right type. In this > case, sprintf('%d', as.integer(NA_real_)) works. > > Best, > > Evan > > On Fri, May 19, 2017 at 9:23 AM, Michael Chirico < > michaelchirico4 at gmail.com> > wrote: > > > Consider > > > > #as.numeric for emphasis > > sprintf('%d', as.numeric(1)) > > # [1] "1" > > > > vs. > > > > sprintf('%d', NA_real_) > > > > > Error in sprintf("%d", NA_real_) : > > > > invalid format '%d'; use format %f, %e, %g or %a for numeric object > > > > > > > I understand the error is correct, but if it works for other numeric > input, > > why doesn't R just coerce NA_real_ to NA_integer_? > > > > Michael Chirico > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-devel at r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > > > > > -- > Evan Cortens, PhD > Institutional Analyst - Office of Institutional Analysis > Mount Royal University > 403-440-6529 > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel >-- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Mathematical Modelling, Statistics and Bio-Informatics tel : +32 (0)9 264 61 79 Joris.Meys at Ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[alternative HTML version deleted]]
Michael Chirico
2017-May-23 16:00 UTC
[Rd] Inconsistency in handling of numeric input with %d by sprintf
Astute observation. And of course we should be passing integer when we use %d. It's an edge case in how we printed ITime objects in data.table: On Tue, May 23, 2017 at 11:53 AM, Joris Meys <jorismeys at gmail.com> wrote:> I initially thought this is "documented behaviour". ?sprintf says: > > Numeric variables with __exactly integer__ values will be coerced to > integer. (emphasis mine). > > Turns out this only works when the first value is numeric and not NA, as > shown by the following example: > > > sprintf("%d", as.numeric(c(NA,1))) > Error in sprintf("%d", as.numeric(c(NA, 1))) : > invalid format '%d'; use format %f, %e, %g or %a for numeric objects > > sprintf("%d", as.numeric(c(1,NA))) > [1] "1" "NA" > > So the safest thing is indeed passing the right type, but the behaviour is > indeed confusing. I checked this on both Windows and Debian, and on both > systems I get the exact same response. > > Cheers > Joris > > On Tue, May 23, 2017 at 4:53 PM, Evan Cortens <ecortens at mtroyal.ca> wrote: > >> Hi Michael, >> >> I posted something on this topic to R-devel several weeks ago, but never >> got a response. My ultimate conclusion is that sprintf() isn't super >> consistent in how it handles coercion: sometimes it'll coerce real to >> integer without complaint, other times it won't. (My particular email had >> to do with the vectors longer than 1 and their positioning vis-a-vis the >> format string.) The safest thing is just to pass the right type. In this >> case, sprintf('%d', as.integer(NA_real_)) works. >> >> Best, >> >> Evan >> >> On Fri, May 19, 2017 at 9:23 AM, Michael Chirico < >> michaelchirico4 at gmail.com> >> wrote: >> >> > Consider >> > >> > #as.numeric for emphasis >> > sprintf('%d', as.numeric(1)) >> > # [1] "1" >> > >> > vs. >> > >> > sprintf('%d', NA_real_) >> > >> > > Error in sprintf("%d", NA_real_) : >> > >> > invalid format '%d'; use format %f, %e, %g or %a for numeric object >> > > >> > >> > I understand the error is correct, but if it works for other numeric >> input, >> > why doesn't R just coerce NA_real_ to NA_integer_? >> > >> > Michael Chirico >> > >> > [[alternative HTML version deleted]] >> > >> > ______________________________________________ >> > R-devel at r-project.org mailing list >> > https://stat.ethz.ch/mailman/listinfo/r-devel >> > >> >> >> >> -- >> Evan Cortens, PhD >> Institutional Analyst - Office of Institutional Analysis >> Mount Royal University >> 403-440-6529 >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-devel at r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >> > > > > -- > Joris Meys > Statistical consultant > > Ghent University > Faculty of Bioscience Engineering > Department of Mathematical Modelling, Statistics and Bio-Informatics > > tel : +32 (0)9 264 61 79 <+32%209%20264%2061%2079> > Joris.Meys at Ugent.be > ------------------------------- > Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php >[[alternative HTML version deleted]]
Michael Chirico
2017-May-23 16:02 UTC
[Rd] Inconsistency in handling of numeric input with %d by sprintf
https://github.com/Rdatatable/data.table/issues/2171 The fix was easy, it's just surprising to see the behavior change almost on a whim. Just wanted to point it out in case this is unknown behavior, but Evan seems to have found this as well. On Tue, May 23, 2017 at 12:00 PM, Michael Chirico <michaelchirico4 at gmail.com> wrote:> Astute observation. And of course we should be passing integer when we use > %d. It's an edge case in how we printed ITime objects in data.table: > > > On Tue, May 23, 2017 at 11:53 AM, Joris Meys <jorismeys at gmail.com> wrote: > >> I initially thought this is "documented behaviour". ?sprintf says: >> >> Numeric variables with __exactly integer__ values will be coerced to >> integer. (emphasis mine). >> >> Turns out this only works when the first value is numeric and not NA, as >> shown by the following example: >> >> > sprintf("%d", as.numeric(c(NA,1))) >> Error in sprintf("%d", as.numeric(c(NA, 1))) : >> invalid format '%d'; use format %f, %e, %g or %a for numeric objects >> > sprintf("%d", as.numeric(c(1,NA))) >> [1] "1" "NA" >> >> So the safest thing is indeed passing the right type, but the behaviour >> is indeed confusing. I checked this on both Windows and Debian, and on both >> systems I get the exact same response. >> >> Cheers >> Joris >> >> On Tue, May 23, 2017 at 4:53 PM, Evan Cortens <ecortens at mtroyal.ca> >> wrote: >> >>> Hi Michael, >>> >>> I posted something on this topic to R-devel several weeks ago, but never >>> got a response. My ultimate conclusion is that sprintf() isn't super >>> consistent in how it handles coercion: sometimes it'll coerce real to >>> integer without complaint, other times it won't. (My particular email had >>> to do with the vectors longer than 1 and their positioning vis-a-vis the >>> format string.) The safest thing is just to pass the right type. In this >>> case, sprintf('%d', as.integer(NA_real_)) works. >>> >>> Best, >>> >>> Evan >>> >>> On Fri, May 19, 2017 at 9:23 AM, Michael Chirico < >>> michaelchirico4 at gmail.com> >>> wrote: >>> >>> > Consider >>> > >>> > #as.numeric for emphasis >>> > sprintf('%d', as.numeric(1)) >>> > # [1] "1" >>> > >>> > vs. >>> > >>> > sprintf('%d', NA_real_) >>> > >>> > > Error in sprintf("%d", NA_real_) : >>> > >>> > invalid format '%d'; use format %f, %e, %g or %a for numeric object >>> > > >>> > >>> > I understand the error is correct, but if it works for other numeric >>> input, >>> > why doesn't R just coerce NA_real_ to NA_integer_? >>> > >>> > Michael Chirico >>> > >>> > [[alternative HTML version deleted]] >>> > >>> > ______________________________________________ >>> > R-devel at r-project.org mailing list >>> > https://stat.ethz.ch/mailman/listinfo/r-devel >>> > >>> >>> >>> >>> -- >>> Evan Cortens, PhD >>> Institutional Analyst - Office of Institutional Analysis >>> Mount Royal University >>> 403-440-6529 >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-devel at r-project.org mailing list >>> https://stat.ethz.ch/mailman/listinfo/r-devel >>> >> >> >> >> -- >> Joris Meys >> Statistical consultant >> >> Ghent University >> Faculty of Bioscience Engineering >> Department of Mathematical Modelling, Statistics and Bio-Informatics >> >> tel : +32 (0)9 264 61 79 <+32%209%20264%2061%2079> >> Joris.Meys at Ugent.be >> ------------------------------- >> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php >> > >[[alternative HTML version deleted]]
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