从R中的环境中删除对象 [英] Deleting objects from environment in R

问题描述

我正在阅读Hadley的高级R.在第8章中，他说我们可以使用 rm（）从环境中删除一个对象。但是，删除后，我仍然可以看到该对象。

I am reading Hadley's Advanced R. In chapter 8, he says that we can remove an object from an environment by using rm(). However, I am still able to see the object after removing it.

这是我的代码：

e<- new.env()
e$a<-1
e$b<-2
e$.a<-3
e$c<-4
ls(e,all.names = TRUE)

#remove the object c
rm("c",envir = e)
ls(e,all.names = TRUE) #Doesn't exist here

#does the variable exist?
exists("c",envir = e) #Shows TRUE. Why is this?
exists("m",envir = e) #FALSE

ls(e,all.names = TRUE)
ls(e)

如上所述，理想情况下，我预计存在（c，envir = e） 返回 FALSE 。

As we can see above, ideally, I'd have expected exists("c", envir = e) to return FALSE.

任何想法？感谢提前。

推荐答案

从帮助（存在） p>

From help(exists):

如果继承是 TRUE 并且在指定环境中找不到 x 的值，将搜索环境的包围框，直到名称 x 遇到。

If inherits is TRUE and a value is not found for x in the specified environment, the enclosing frames of the environment are searched until the name x is encountered.

命名变量时要小心。您与基础函数 c（）有冲突。由于 inherits = TRUE 是默认值，所以搜索包围的环境，在这种情况下，基本函数 c（）发现，它产生 TRUE 结果。因此，要仅搜索环境 e 然后退出，请使用 inherits = FALSE 。

Be careful when naming your variables. You have a conflict with the base function c(). Since inherits = TRUE is the default, the enclosing environments are searched and in this case the base function c() is found, which produces the TRUE result. Therefore, to search only the environment e and then quit, use inherits = FALSE.

exists("c", envir = e, inherits = FALSE)
# [1] FALSE

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