In the code for 'aggregate.formula', there is if (as.character(formula[[2L]] == ".")) I believe that it is meant to be if (as.character(formula[[2L]]) == ".")
However, if (as.character(formula[[2L]] == ".")) gives the expected result. Tracing: - formula[[2L]] == "." is equivalent to as.character(formula[[2L]]) == "." >From the help page for '==' (Comparison), "Language objects such as symbols >and calls are deparsed to character strings before comparison." - By applying 'as.character', the TRUE/FALSE result of formula[[2L]] == "." is converted to character, becomes "TRUE"/"FALSE". - Then, for 'if', it is implicitly converted back to logical. > sessionInfo() R version 2.14.2 (2012-02-29) Platform: i386-pc-mingw32/i386 (32-bit) locale: [1] LC_COLLATE=English_United States.1252 [2] LC_CTYPE=English_United States.1252 [3] LC_MONETARY=English_United States.1252 [4] LC_NUMERIC=C [5] LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base I see that, in R 2.15.1, the code for 'aggregate.formula' is still the same. ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
