rm（list = ls（））不会完全清除工作区
这是一个非常小的问题，但我想明确地知道这里发生了什么。
假设我执行以下操作：
library(RMySQL)
con <- dbConnect(MySQL(), host="some.server.us-east-1.rds.amazonaws.com",user="aUser", password="password", dbname="mydb")
values1 <- dbGetQuery(con,"select x,y from table1")
attach(values1)
在这一点上，我可以做到
rm(list=ls())
values2 <- dbGetQuery("select x,y from table1")
attach(values2)
但附件给了我一个关于屏蔽x和y的警告。 我以为我已经破坏了那些。 到底是怎么回事？ 我如何完全清除工作区？
attach()不会在您的全局环境中创建x和y副本，它会将数据框附加到搜索路径。
来自?attach ：
The database is not actually attached. Rather, a new environment
is created on the search path and the elements of a list
(including columns of a data frame) or objects in a save file or
an environment are _copied_ into the new environment. If you use
‘<<-’ or ‘assign’ to assign to an attached database, you only
alter the attached copy, not the original object. (Normal
assignment will place a modified version in the user's workspace:
see the examples.) For this reason ‘attach’ can lead to
confusion.
例如：
> search()
[1] ".GlobalEnv" "package:stats" "package:graphics"
[4] "package:grDevices" "package:utils" "package:datasets"
[7] "package:methods" "Autoloads" "package:base"
> a <- data.frame(stuff=rnorm(100))
> search()
[1] ".GlobalEnv" "package:stats" "package:graphics"
[4] "package:grDevices" "package:utils" "package:datasets"
[7] "package:methods" "Autoloads" "package:base"
> attach(a)
> search()
[1] ".GlobalEnv" "a" "package:stats"
[4] "package:graphics" "package:grDevices" "package:utils"
[7] "package:datasets" "package:methods" "Autoloads"
[10] "package:base"
> rm(list=ls())
> search()
[1] ".GlobalEnv" "a" "package:stats"
[4] "package:graphics" "package:grDevices" "package:utils"
[7] "package:datasets" "package:methods" "Autoloads"
[10] "package:base"
> stuff
[1] -0.91436377 0.67397624 0.62891651 -0.99669584 2.07692590 -0.62702302
[...]
> detach(a)
> search()
[1] ".GlobalEnv" "package:stats" "package:graphics"
[4] "package:grDevices" "package:utils" "package:datasets"
[7] "package:methods" "Autoloads" "package:base"
只需要提及......如果你的环境中隐藏了对象，比如.First和.Last函数，你可以使用rm(list = ls(all.names = TRUE))来删除它们。 但在你的情况下，使用detach(objectname)从搜索路径中删除对象。 detach()将删除位置＃2中的任何对象，因为.GlobalEnv不能被删除（并且也是base ）。 使用detach()你可以卸载以前加载的软件包，所以要小心（尽管你可以随时加载library(packagename) ）。
R本身说，在rm的帮助中：
## remove (almost) everything in the working environment.
## You will get no warning, so don't do this unless you are really sure.
rm(list = ls())
注意'几乎'。 有不同的环境。
你尝试detach(values1)吗？