You wrote: The correct and logical way (which I use in 'eha') is to check if input is a data frame, and if not, throw an error.
If you want to check for a data frame (and a data frame only), because you don't want to coerce *any* object to data frames, then this would be one way to check for df/tibble, and coerce tibbles only. That's what I had in mind... But as I mentioned before, since simplifying is the most (or even only?) relevant point when dealing with tibbles, I have re-written all parts in my packages that used df[, x] indexing, and replaced with df[[x]], resp. used df[, x, drop = FALSE], or - if a vector is needed - you can use "dplyr::pull()" to make sure you get a vector. Best Daniel -----Ursprüngliche Nachricht----- Von: Gábor Csárdi [mailto:csardi.ga...@gmail.com] Gesendet: Dienstag, 26. September 2017 12:15 An: Daniel Lüdecke <d.luede...@uke.de> Cc: R Package Devel <r-package-devel@r-project.org> Betreff: Re: [R-pkg-devel] tibbles are not data frames What is the benefit here, compared to just calling as.data.frame() on it? Gabor On Tue, Sep 26, 2017 at 11:11 AM, Daniel Lüdecke <d.luede...@uke.de> wrote: > Since tibbles add their class attributes first, you could use: > > tb <- tibble(a = 5) > inherits(tb, "data.frame", which = TRUE) == 1 > > if "tb" is a data frame (only), TRUE is returned, for tibble FALSE. > You could then coerce to data frame: as.data.frame(tb) > > -----Ursprüngliche Nachricht----- > Von: R-package-devel [mailto:r-package-devel-boun...@r-project.org] Im > Auftrag von Göran Broström > Gesendet: Dienstag, 26. September 2017 12:09 > An: r-package-devel@r-project.org > Betreff: Re: [R-pkg-devel] tibbles are not data frames > > > > On 2017-09-26 11:56, Gábor Csárdi wrote: >> On Tue, Sep 26, 2017 at 10:35 AM, Joris Meys <joris.m...@ugent.be> wrote: >>> I don't like the dropping of dimensions either. That doesn't change >>> the fact that a tibble reacts different from a data.frame. So >>> tibbles do not inherit correctly from the class data.frame, and it >>> can thus be argued that it's against OOP paradigms to pretend >>> tibbles inherit from the class data.frame. >> >> I have yet to see an OOP system in which a subclass cannot override >> the methods of its superclass. Not only is this in line with OOP >> paradigms, it is actually one of the essential OOP features. >> >> To be more constructive, if you have a function that only works with >> data frame inputs, then it is good practice to check that the >> supplied input is indeed a data frame. This is independent of tibbles. > > It is not. I check input for being a data frame, but tibbles pass that test. > That's the essence of the problem. > >> In practice it seems to me that an easy fix is to just call >> as.data.frame on the input. This should either convert it to a data >> frame, or throw an error. > > Sure, but I still need to rewrite the package. > > Görn > >> For tibbles it >> drops the tbl* classes. >> >> Gabor >> >>> Defensive coding techniques would check if it's a tibble and return >>> an error saying a data.frame is expected. Unless tibbles inherit >>> correctly from data.frame. >>> >>> I have nothing against tibbles. But calling them "data.frame" raises >>> expectations that can't be fulfilled. >> >> [...] >> >> ______________________________________________ >> R-package-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-package-devel >> > > ______________________________________________ > R-package-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-package-devel > > -- > > _____________________________________________________________________ > > Universitätsklinikum Hamburg-Eppendorf; Körperschaft des öffentlichen > Rechts; Gerichtsstand: Hamburg | www.uke.de > Vorstandsmitglieder: Prof. Dr. Burkhard Göke (Vorsitzender), Prof. Dr. > Dr. Uwe Koch-Gromus, Joachim Prölß, Martina Saurin (komm.) > _____________________________________________________________________ > > SAVE PAPER - THINK BEFORE PRINTING > ______________________________________________ > R-package-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-package-devel -- _____________________________________________________________________ Universitätsklinikum Hamburg-Eppendorf; Körperschaft des öffentlichen Rechts; Gerichtsstand: Hamburg | www.uke.de Vorstandsmitglieder: Prof. Dr. Burkhard Göke (Vorsitzender), Prof. Dr. Dr. Uwe Koch-Gromus, Joachim Prölß, Martina Saurin (komm.) _____________________________________________________________________ SAVE PAPER - THINK BEFORE PRINTING ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
