从函数中删除.GlobalEnv中的对象 [英] Remove objects in .GlobalEnv from within a function

问题描述

我想创建一个函数(CleanEnvir)，该函数基本上调用remove/rm并从.GlobalEnv中删除某些对象.

I would like to create a function (CleanEnvir) which basically calls remove/rm and which removes certain objects from .GlobalEnv.

  CleanEnvir <- function(pattern = "tmp"){
      rm(list = ls()[grep("tmp", ls())], envir = globalenv())
  }

  keep <- 1
  tmp.to.be.removed <- 0
  ls()

  ## does not work
  CleanEnvir()
  ls()

  ## does work
  rm(list = ls()[grep("tmp", ls())], envir = globalenv())
  ls()

推荐答案

ls()需要在正确的位置查找.默认情况下，它会在当前帧中查找CleanEnvir函数的当前帧，因此只能在原始帧中找到"pattern".

ls() needs to look in the correct place. By default it looks in the current frame, that of the function CleanEnvir in your case and hence was only finding "pattern" in your original.

CleanEnvir <- function(pattern = "tmp") {
    objs <- ls(pos = ".GlobalEnv")
    rm(list = objs[grep("tmp", objs)], pos = ".GlobalEnv")
}

哪个给:

> CleanEnvir <- function(pattern = "tmp") {
+     objs <- ls(pos = ".GlobalEnv")
+     rm(list = objs[grep("tmp", objs)], pos = ".GlobalEnv")
+ }
> ls()
[1] "CleanEnvir"        "foo"               "keep"             
[4] "tmp.to.be.removed"
> CleanEnvir()
> ls()
[1] "CleanEnvir" "foo"        "keep"

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