Dear list members, I'm a bit confused about the evaluation of expressions using with() or within() versus subset() and transform(). I always teach my students to use with() and within() because of the warning mentioned in the helppages of subset() and transform(). Both functions use nonstandard evaluation and are to be used only interactively.
I've never seen that warning on the help page of with() and within(), so I assumed both functions can safely be used in functions and packages. I've now been told that both functions pose the same risk as subset() and transform(). Looking at the source code I've noticed the extra step: e <- evalq(environment(), data, parent) which, at least according to my understanding, should ensure that the functions follow the standard evaluation rules. Could somebody with more knowledge than I have shed a bit of light on this issue? Thank you Joris -- 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.m...@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
