R help - Jul 2010 - Fwd: setMethod( '[', c( 'data.frame', 'expression' ...

Hi,

I am trying to write a method for [,data.frame,expression.  But it give the
error:
*
*
*Error in xj[i] : invalid subscript type 'expression'*

I looked at the help files and the archives.  No avail.  Any ideas?  Here is
an example that reproduces the error.
> setGeneric( '[' )
[1] "["
>  setMethod( '[', c( 'data.frame', 'expression',
'ANY', 'ANY' ),
+   function(x, i, j, ..., drop ) { 1 }
+ )
[1] "["
> iris[ expression(1), ]
Error in xj[i] : invalid subscript type 'expression'

This is running R-2.11.1 on Windows and Linux.

Thanks in Advance,

Chris

Open Data
  http://www.opendatagroup.com
  http://opendatagroup.com/category/blog

	[[alternative HTML version deleted]]