Universitätsklinikum Hamburg-Eppendorf; Körperschaft des öffentlichen Rechts; Gerichtsstand: Hamburg | www.uke.de
Vorstandsmitglieder: Prof. Dr. Burkhard Göke (Vorsitzender), Joachim Prölß, Prof. Dr. Blanche Schwappach-Pignataro, Marya Verdel
> I'm not sure if the following is intended, or a bug, but "all.vars()"
> returns different values, depending on whether "TRUE" or "T" is used inside
> "poly()": >
> m1 <- lm(Sepal.Length ~ poly(Sepal.Width, 2, raw = TRUE) + Petal.Length,
> data = iris)
> m2 <- lm(Sepal.Length ~ poly(Sepal.Width, 2, raw = T) + Petal.Length, data =
> #>  "Sepal.Length" "Sepal.Width" "Petal.Length"
> #>  "Sepal.Length" "Sepal.Width" "T" "Petal.Length"
> I know that "T" is no reserved word, but rather a global variable.
> Nonetheless, I just wanted to be clear if there is a bug, or everything
> works as intended.
It looks as though it is working as documented. formula(m2) gives
Sepal.Length ~ poly(Sepal.Width, 2, raw = T) + Petal.Length
and all.vars says it returns "a character vector containing all the
names which occur in an expression or call." "T" is a name.
There are good reasons why "R CMD check" warns about using T when you