What the difference between .Golbalenv and package:base?

As you know, in the search path, there is .GlobalEnv, package:stats and so
on, why do we need to convert the character "package:stats" to the stats
environment.
I mean, why don't let package:stats be a environment type object like
.GlobalEnv,but let it be a string ?
Hope you understand my meaning for my pool english expression way.

Yes, you have  Sorry for my misunderstanding of what were originally
saying. I _think_ that I now understand. The fault is likely my
concentrating on the wrong part of your original email. To test my
ability to understand, I submit the following possibility:

new_name<-new.env();
attach(new_name)
search()

[1] ".GlobalEnv"        "new_name"          "new_name"
"tools:rstudio"
 [5] "package:graphics"  "package:grDevices" "package:utils"
"package:datasets"
 [9] "package:methods"   "Autoloads"         "package:base"

assign("a",2,pos="new_name")
a

[1] 2

ls()

[1] "new_name"

ls(pos="new_name")

[1] "a"

Note the use of pos= instead of envir=. That seems to be the key here.
I hope this was of more use to you. One problem that I have noticed is
that you can not get to the value of "a" by using "new_name$a", but
must use the get() function like: get('a',pos='new_name');

Please be very aware of the following, very confusing fact:
Referencing a variable can not have the expected results.

new_name <- new.env()
attach(new_name)
search()

[1] ".GlobalEnv"        "new_name"          "tools:rstudio"
"package:stats"
 [5] "package:graphics"  "package:grDevices" "package:utils"
"package:datasets"
 [9] "package:methods"   "Autoloads"         "package:base"

assign("a",2,"new_name")
ls()

[1] "new_name"

new_name$a

NULL

get("a",pos="new_name")

[1] 2

new_name$a <- 'x'
new_name$a;

[1] "x"

get("a",pos="new_name")

[1] 2

If you wanted to use string values in the first two commands above,
then perhaps:

attach(NULL,name="new_name")
search()

[1] ".GlobalEnv"        "new_name"          "tools:rstudio"
"package:graphics"
 [5] "package:grDevices" "package:utils"     "package:datasets"
"package:methods"
 [9] "Autoloads"         "package:base"

assign("a",2,pos="new_name")
ls()

character(0)

ls(pos="new_name")

[1] "a"

a

[1] 2

# or even
ls("new_name")

[1] "a"

Likewise you can do:

search()

[1] ".GlobalEnv"        "tools:rstudio"     "package:stats"
"package:graphics"
 [5] "package:grDevices" "package:utils"     "package:datasets"
"package:methods"
 [9] "Autoloads"         "package:base"

ls(pos="package:stats")

[1] "acf"                  "acf2AR"               "add.scope"
  [4] "add1"                 "addmargins"           "aggregate"
  [7] "aggregate.data.frame" "aggregate.ts"         "AIC"
 [10] "alias"                "anova"                "ansari.test"
...
[436] "variable.names"       "varimax"              "vcov"
[439] "weighted.mean"        "weighted.residuals"   "weights"
[442] "wilcox.test"          "window"               "window<-"
[445] "write.ftable"         "xtabs"

get("time",pos="package:stats")

function (x, ...)
UseMethod("time")
<bytecode: 0x000000000a4e8b00>
<environment: namespace:stats>

x<-get("time",pos="package:stats")
x

function (x, ...)
UseMethod("time")
<bytecode: 0x000000000a4e8b00>
<environment: namespace:stats>

# note that the get() basically created a variable in the global environment whose value was
# the same as in the package. But you can change the value of "x" in the global environment
# and it won't affect the value in the package. And vice versa, if you could update "x" in
# the package, but that can't be done because packages seem to be locked and read-only.

--
PO SU
mail: desolator88 at 163.com
Majored in Statistics from SJTU

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