[Rd] is.vector(as.vector(x, m), m) not always TRUE

Hervé Pagès hpages at fhcrc.org
Wed Apr 24 01:48:42 CEST 2013

In the man page for as.vector() (same as man page for vector()):

      Writers of methods for ‘as.vector’ need to take care to follow the
      conventions of the default method.  In particular

         • Argument ‘mode’ can be ‘"any"’, any of the atomic modes,
           ‘"list"’, ‘"expression"’, ‘"symbol"’, ‘"pairlist"’ or one of
           the aliases ‘"double"’ and ‘"name"’.

         • The return value should be of the appropriate mode.  For
           ‘mode = "any"’ this means an atomic vector or list.

         • Attributes should be treated appropriately: in particular
           when the result is an atomic vector there should be no
           attributes, not even names.

         • ‘is.vector(as.vector(x, m), m)’ should be true for any mode
           ‘m’, including the default ‘"any"’.


   > is.vector(as.vector("a", "name"), "name")
   [1] FALSE

Mmmh, the default method itself doesn't seem to follow its own
conventions :-/


 > sessionInfo()
R version 3.0.0 (2013-04-03)
Platform: x86_64-unknown-linux-gnu (64-bit)

  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
  [7] LC_PAPER=C                 LC_NAME=C
  [9] LC_ADDRESS=C               LC_TELEPHONE=C

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

loaded via a namespace (and not attached):
[1] tools_3.0.0

Hervé Pagès

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024

E-mail: hpages at fhcrc.org
Phone:  (206) 667-5791
Fax:    (206) 667-1319

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