r - How do you determine the namespace of a function?

Question

Given a function, how do you determine which namespace it has come from?

For example, if I type mean.default at the command prompt, the output includes the fact that it is in the base package. I want to be able to do something like getNamespace(mean.default) and have it return "base" (or the actual base environment).

There is a getNamespace function but seems to only accept package names rather than function names.

print.function uses internal code to retrieve the namespace. I got as far as browsing do_printfunction in src/main/print.c but then gave up.

Answer 1

I very recently learned about find() which seems to do just this.

R> find("ls")
[1] "package:base"
R> find("na.locf")
[1] "package:zoo"