[Rd] S3 weirdness

[Simon Urbanek]

Gabor,

just by using zoo::read.zoo() you *do* load the namespace:

> args(zoo::read.zoo)
function (file, format = "", tz = "", FUN = NULL, regular = FALSE, 
    index.column = 1, drop = TRUE, FUN2 = NULL, split = NULL, 
    aggregate = FALSE, ..., text, read = read.table) 
NULL
> sessionInfo()
R Under development (unstable) (2021-06-23 r80548)
Platform: x86_64-apple-darwin19.6.0 (64-bit)
Running under: macOS Catalina 10.15.7

Matrix products: default
BLAS:   /Volumes/Builds/R/build/lib/libRblas.dylib
LAPACK: /Volumes/Builds/R/build/lib/libRlapack.dylib

locale:
[1] en_NZ.UTF-8/en_NZ.UTF-8/en_NZ.UTF-8/C/en_NZ.UTF-8/en_NZ.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
[1] zoo_1.8-9       compiler_4.2.0  grid_4.2.0      lattice_0.20-44

which includes S3 method dispatch tables:

> methods(as.ts)
[1] as.ts.default* as.ts.zoo*     as.ts.zooreg* 
see '?methods' for accessing help and source code

so the behavior is as expected.

Cheers,
Simon


> On 25/06/2021, at 9:56 AM, Gabor Grothendieck <ggrothendieck using gmail.com> wrote:
> 
> If we start up a vanilla session of R with no packages loaded and
> type the single line of code below as the first line entered then
> we get the output shown below.  The NA in the output and the length
> of 7 indicate that as.ts dispatched as.ts.zoo since as.ts.default
> would have resulted in a length of 6 with no NA's. It should not have
> known about as.ts.zoo since we never  explicitly loaded the zoo
> package using library or require.
> zoo:: was only used to refer to read.zoo.  This seems to be a bug in
> the way R is currently working.
> 
>  as.ts(zoo::read.zoo(BOD))
>  ## Time Series:
>  ## Start = 1
>  ## End = 7
>  ## Frequency = 1
>  ## [1]  8.3 10.3 19.0 16.0 15.6   NA 19.8
> 
>  R.version.string
>  ## [1] "R version 4.1.0 RC (2021-05-16 r80303)"
> 
> -- 
> Statistics & Software Consulting
> GKX Group, GKX Associates Inc.
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> email: ggrothendieck at gmail.com
> 
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