Variable Wildcard Value
Hi,
Since you insist, here is something that I think matches the
specifications :
wildcard <- function( ) structure( NULL, class = "wildcard" )
Ops.wildcard <- function (e1, e2){
if (nargs() == 1L)
return( e1 )
result <- switch(.Generic,
`<` = , `>` = , `==` = ,
`<=` = , `>=` = TRUE, `!=` = FALSE)
result
}
is.na.wildcard <- function( x ) FALSE
> w == 1
[1] TRUE
> w == "peanut butter"
[1] TRUE
> is.na( w )
[1] FALSE
> "peanut butter" == w
[1] TRUE
> w == w
[1] TRUE
> w != w
[1] FALSE
# Is negation of a wildcard also a wildcard, or should it be a bizarro
wildcard ?
> (!w) == 2
[1] TRUE
Not really sure how this could be useful though, and would also be
interested in Francis end game.
Romain
Patrick Burns wrote:
I would be truly amazed if the answer were "yes". I find this the most fascinating question on R-help for a long time, maybe ever. Can you tell us what you have in mind and what your ultimate purpose is? Patrick Burns patrick at burns-stat.com +44 (0)20 8525 0696 http://www.burns-stat.com (home of "The R Inferno" and "A Guide for the Unwilling S User") Francis Smart wrote:
Is there a wildcard value for vector values in r? For instance:
M <- *wildcard
(M==1)
TRUE
(M=="peanut butter")
TRUE
is.na(M)
FALSE thanks, Francis
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Romain Francois Independent R Consultant +33(0) 6 28 91 30 30 http://romainfrancois.blog.free.fr