[R] bugs or imperfect implementation?

Chong Gu
Fri, 08 Feb 2002 14:26:20 -0000

I am using R to teach, and here are a couple of things that I thought
would work didn't work.

1. I noticed the utility data(***,package=***) recently and like it
very much, but unless I type in the whole word "package" I'll get
an
error in 1.4.0.  For example, data(cats,package=MASS) works fine but
data(cats,pac=MASS) doesn't.

2. drop1 doesn't seem to be as smart as before.  In the sequence
below, drop1 didn't produce what I expected it to produce.

    data(HairEyeColor); lab<-dimnames(HairEyeColor)
    HairEye<-cbind(expand.grid(Hair=lab$Hair,Eye=lab$Eye,
        Sex=lab$Sex),Fr=as.vector(HairEyeColor))
    HairEye.fit<-glm(Fr~.^2,poisson,HairEye)
    drop1(HairEye.fit)

The following sequence however works.

    HairEye.fit<-glm(Fr~(Hair+Eye+Sex)^2,poisson,HairEye)
    drop1(HairEye.fit)

Chong Gu