[R] detach

[Roger Peng]

I believe (3) should always work as long as zoo has a namespace.  The
':::' operator will load the namespace of the package but will not
attach it to the search list.

-roger

On 7/11/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> We try the following:
>
> search()
> as.Date(1)
> zoo:::as.Date.numeric
>
> under three circumstances:
>
> 1. on a fresh session
> 2. after issuing library(zoo) noting that as.Date.numeric is provided by zoo
> 3. after detaching zoo
>
> as.Date(1) fails on #1 but succeeds in #2 and #3.  Should it not fail in #3
> since zoo was detached?  Is this how its supposed to work?
>
> (Note that entering zoo:::as.Date.numeric at the console
> succeeds in displaying the function in all three cases.)
>
> Here is the console session:
>
> > R.version.string # XP
> [1] "Version 2.3.1 Patched (2006-06-04 r38279)"
> >
> > search()
> [1] ".GlobalEnv"        "package:methods"   "package:stats"
> [4] "package:graphics"  "package:grDevices" "package:utils"
> [7] "package:datasets"  "Autoloads"         "package:base"
> > as.Date(1)
> Error in as.Date.default(1) : do not know how to convert '1' to class "Date"
> > zoo:::as.Date.numeric
> function (x, ...)
> structure(floor(x + 0.001), class = "Date")
> <environment: namespace:zoo>
> >
> > library(zoo)
> > search()
>  [1] ".GlobalEnv"        "package:zoo"       "package:methods"
>  [4] "package:stats"     "package:graphics"  "package:grDevices"
>  [7] "package:utils"     "package:datasets"  "Autoloads"
> [10] "package:base"
> > as.Date(1)
> [1] "1970-01-02"
> > zoo:::as.Date.numeric
> function (x, ...)
> structure(floor(x + 0.001), class = "Date")
> <environment: namespace:zoo>
> >
> > detach()
> > search()
> [1] ".GlobalEnv"        "package:methods"   "package:stats"
> [4] "package:graphics"  "package:grDevices" "package:utils"
> [7] "package:datasets"  "Autoloads"         "package:base"
> > as.Date(1)
> [1] "1970-01-02"
> > zoo:::as.Date.numeric
> function (x, ...)
> structure(floor(x + 0.001), class = "Date")
> <environment: namespace:zoo>
> >
>
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-- 
Roger D. Peng  |  http://www.biostat.jhsph.edu/~rpeng/