R 中 mean 的对象类型是什么？

Question

我正在寻找R中某些函数的真实对象类型，例如，我找不到mean函数的对象类型。

> library(pryr)
> otype(mean)
[1] "base"
> ftype(mean)
[1] "s3"      "generic"

有时候均值函数是S3，有时候是base！

Answer 1

ftype 告诉我们什么？

This function figures out whether the input function is a regular/primitive/internal function, a internal/S3/S4 generic, or a S3/S4/RC method. This is function is slightly simplified as it’s possible for a method from one class to be a generic for another class, but that seems like such a bad idea that hopefully no one has done it.

otype 给了我们什么？

Figure out which object system an object belongs to:

• base: no class attribute

• S3: class attribute, but not S4

• S4: isS4, but not RC

• RC: inherits from "refClass"

供参考：

R 中 mean 的对象类型是什么？

what is the object type of mean in R?

r

pryr