The most interesting thing in this thread for me was "within()" - that is what
I want 99% of the time, but I had only ever heard of with()
A real boon! Thanks Bill V!
The help for within gives this example for with(), which seems unnecessary, as
glm supports data=
with(anorexia, {
anorex.1 <- glm(Postwt ~ Prewt + Treat + offset(Prewt), family = gaussian)
summary(anorex.1)
})
especially when this is easier to read:
m <- glm(Postwt ~ Prewt + Treat + offset(Prewt), family = gaussian,
data=anorexia)
summary(m)
The Rd file also has (just?) one example for within… I suggest deleting the
anorexia example so the within example comes first, and perhaps supplementing
with
## Not run:
# More advanced example of usage (not run)
model1 <- glm.nb(Cells ~ Cryogel*Day, data = myData)
myData2 <- within(myData, Cryogel <- relevel(Cryogel, ref = "2"))
model2 <- update(model1, data = myData1)
## End(Not run)
Also, the help page for transform does not back link to within… That would be
helpful. It also uses an example with attach, which might encourage less good
habits.
Best wishes, and thanks,
tim
PS : How does one best contribute to help files?
PPS: If R was to go to google summer of code, apart from helpful help, my
wishlist would prioritise standardising all common functions to (where possible)
1. Have a formula interface
2. Support “data=“
3. Use a uniform na handling, with examples
Diverse NA behavior catches most of our students out (now all three departments
of our school using R exclusively at the PG level)
NA behaviour can be
na.rm= as in rowMeans(na.rm=T))
use= as in an cor(use=“every”) # with well documented effects in
?cor(), and all legal options shown
(everything|all.obs|complete.obs|na.or.complete|pairwise.complete.obs)
na.action= as in t.test(na.action=“na.omit”) # with no examples in ?t.test,
nor a list of legal values
Likewise it would help reduce confusion when
plot(~Source, data=Df) # works
# but
boxplot(~Source, data=Df)
# Error in boxplot.formula(~Source, data = Df) :
# 'formula' missing or incorrect
The formula isn’t missing or illformed, it’s that boxplot requires formulae to
have something on the left hand side.
best, t
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