New installation seems to have behavior I cannot figure out. Here is
illustrative sequence where I load a small data set (test) from Crawley's files
and try to run a simple linear model and get an error message. Oddly, R
reports that the variable 'test$ozone' is numeric while, after attaching test,
the variable ozone is not numeric. Can someone please help? This behavior is
occurring with multiple data sets loaded from outside R. Thank you in advance.
Michael Grant
Example:
> test
ozone garden
1 3 A
2 5 B
3 4 A
4 5 B
5 4 A
6 6 B
7 3 A
8 7 B
9 2 A
10 4 B
11 3 A
12 4 B
13 1 A
14 3 B
15 3 A
16 5 B
17 5 A
18 6 B
19 2 A
20 5 B
> is.data.frame(test)
[1] TRUE
> is.numeric(test$ozone)
[1] TRUE
> is.factor(test$garden)
[1] TRUE
> lm(ozone~garden)
Error in model.frame.default(formula = ozone ~ garden, drop.unused.levels =
TRUE) :
invalid type (list) for variable 'ozone'
> attach(test)
> is.numeric(ozone)
[1] FALSE
> is.numeric(test$ozone)
[1] TRUE
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
