I was writing some assertion tests for modelling-related code I had written and was surprised to see one test fail because the "specials" attribute of the output of terms() is a "pairlist" instead of a "list". In 2.12.0 I get:
> dput(attr(terms(y~Spec(x1)+x2, specials=c("Spec")), "specials")) list(Spec = 2L) > all.equal(attr(terms(y~Spec(x1)+x2, specials=c("Spec")), "specials"), list(Spec=2L)) [1] "Modes: pairlist, list" > all.equal(attr(terms(y~Spec(x1)+x2, specials=c("Spec")), "specials"), pairlist(Spec=2L)) [1] TRUE > identical(attr(terms(y~Spec(x1)+x2, specials=c("Spec")), "specials"), pairlist(Spec=2L)) [1] TRUE I was wondering if there was a reason for using pairlist instead of list here or it it was just an historical artifact. In general, when should one use pairlists? Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel