Re: [Rd] Missing argument vs. empty argument

2011-01-25 Thread Renaud Gaujoux
My purpose is indeed to write a '[' method. I will go for the `[.data.frame` solution then. Thank you. On 25/01/2011 12:53, Prof Brian Ripley wrote: On Tue, 25 Jan 2011, Renaud Gaujoux wrote: Hi, is there an easy, robust, and/or recommended way to distinguish a missing argument from an empt

Re: [Rd] Missing argument vs. empty argument

2011-01-25 Thread Prof Brian Ripley
On Tue, 25 Jan 2011, Renaud Gaujoux wrote: Hi, is there an easy, robust, and/or recommended way to distinguish a missing argument from an empty argument as in: An empty argument is a missing argument when argument matching is done, e.g. foo <- function(i,j) match.call() foo(i) foo(i = i