Given the documentation in ?is.object and the info in R Internals section 1.1.2, I'd argue that this indeed a bug.
Looking at https://github.com/wch/r-source/blob/trunk/src/library/stats/src/model.c (line 220 and following) the function copyMostAttribNoTs is called to copy the attributes lost after the na.action. This decision makes sense, but when I look at that functiion copyMostAttribNoTs it sets the object bit to the original state of the input, whereas in the case of a ts object, both the class and the tsp attribute were dropped and not restored. More specifically, line 338 of https://github.com/wch/r-source/blob/3d0650af456d97648c72de66a40b85d3ec96a497/src/main/attrib.c is imho the place where the object bit is set on a previous ts object that lost its attributes, and if I read R Internals correctly, that shouldn't happen. Cheers Joris On Mon, Mar 5, 2018 at 4:59 PM, Michael Chirico <michaelchiri...@gmail.com> wrote: > Full thread here: > > https://github.com/tidyverse/broom/issues/287 > > Reproducible example: > > is.object(freeny$y) > # [1] TRUE > attr(freeny$y, 'class') > # [1] "ts" > class(freeny$y) > # [1] "ts" > > # ts attribute wiped by model.frame > class(model.frame(y ~ ., data = freeny)$y) > # [1] "numeric" > attr(model.frame(y ~ ., data = freeny)$y, 'class') > # NULL > > # but still: > is.object(model.frame(y ~ ., data = freeny)$y) > # [1] TRUE > > That is, given a numeric vector with class "ts", model.frame strips the > "ts" attribute but keeps the is.object property. > > This behavior is alluded to in ?model.frame: > > Unless na.action = NULL, time-series attributes will be removed from the > > variables found (since they will be wrong if NAs are removed). > > > > And in fact explicitly setting na.action = NULL prevents dropping the > class: > > class(model.frame(y ~ ., data = freeny, na.action = NULL)$y) > # [1] "ts" > > The reason this looks especially like a bug is that it differs from how > na.omit behaves: > > DF <- data.frame(x = c(1, 2, 3), y = c(0, 10, NA)) > is.object(DF$y) > # [1] FALSE > class(DF$y) = 'foo' > is.object(DF$y) > # [1] TRUE > class(na.omit(DF)$y) > # [1] "numeric" > is.object(na.omit(DF)$y) > # [1] FALSE > > > That is, similarly presented with a classed object, na.omit strips the > class *and* the OBJECT attribute. > > Thanks, > Michael Chirico > > [[alternative HTML version deleted]] > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > -- Joris Meys Statistical consultant Department of Data Analysis and Mathematical Modelling Ghent University Coupure Links 653, B-9000 Gent (Belgium) <https://maps.google.com/?q=Coupure+links+653,%C2%A0B-9000+Gent,%C2%A0Belgium&entry=gmail&source=g> ----------- Biowiskundedagen 2017-2018 http://www.biowiskundedagen.ugent.be/ ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
