[R] apropos and find

[Gavin Simpson]

On Tue, 2010-04-20 at 10:24 +0200, Karsten Rincke wrote:
> Hello,
> I'm starting working myself in the use of R, reading M. J. Crawley, The
> R Book. The problem I do encounter is concerning the commands apropos
> and find:
> 
> > apropos(edit)
> Fehler: is.character(what) is not TRUE
> > find(edit)
> Fehler: is.character(what) is not TRUE
> 
> I get the same error message typing anything else instead of "edit".

>From ?apropos

Usage:

     apropos(what, where = FALSE, ignore.case = TRUE, mode = "any")
     
     find(what, mode = "any", numeric = FALSE, simple.words = TRUE)
     
Arguments:

    what: character string with name of an object, or more generally a
          regular expression to match against.

And edit is not a character string but "edit" is. Hence the very clear
error.

> The command ?edit seems to work well.

>From ?"?"

Usage:

     ?topic
     
     type?topic
     
Arguments:

   topic: Usually, a name or character string specifying the topic for
          which help is sought.

          Alternatively, a function call to ask for documentation on a
          corresponding S4 method: see the section on S4 method
          documentation.  The calls ‘pkg::topic’ and ‘pkg:::topic’ are
          treated specially, and look for help on ‘topic’ in package
          ‘pkg’.

Hence `?` allows a wider range of object types for it's argument topic.

> What could be the reason for that I can't use apopos and find?

You aren't providing a character a string. Not sure where you got the
usage you are using from, but it is wrong. The docs are quite clear
here.

HTH

G

> Thanks for your help!
> 
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