[R] as.list cannot handle an environment

Wacek Kusnierczyk Waclaw.Marcin.Kusnierczyk at idi.ntnu.no
Tue Mar 24 15:25:44 CET 2009

?as.list states that as.list can be used with environments as arguments
(what is referred to there as the '"environment" method for as.list). 

    e = globalenv()
    # $e
    # <environment: R_GlobalEnv>

however, it seems to have problems with environment objects with a class

    e = structure(globalenv(), class='foo')
    # Error in as.vector(x, "list") :
    #  cannot coerce type 'environment' to vector of type 'list'

the error message is misleading.  instead of complaining about the class
'foo', it says that as.list cannot coerce an environment to a list,
which is nonsense, since this is precisely what it does in the first
example above, and what is also clear from ?as.list:

 The '"environment"' method for 'as.list' copies the name-value
     pairs (for names not beginning with a dot) from an environment to
     a named list.

a different error message might be more appropriate.


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