Makes sense if you realize that ?"[" only applies to *vector*,
*list*, and *matrix* indexing and that data frames follow their own
rules that are documented elsewhere ...
So yes, not a bug but I claim it's an infelicity. I might submit a
doc patch.
FWIW
b["A1",]
as.matrix(b)["A1",]
I don't think this is a bug in the documentation. The help page for
`?[.data.frame` has the following in the last paragraph of the
details:
Both [ and [[ extraction methods partially match row names. By default
neither partially match column names, but [[ will if exact = FALSE
(and with a warning
