[R] A %nin% operator?

[David Huffer]

See Harrell's Hmisc package

--
 David Huffer, Ph.D.
 Deputy Director
 CSOSA/ORE
 Washington, DC

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Ken Williams
Sent: Thursday, August 05, 2010 11:20 AM
To: r-help at r-project.org
Subject: [R] A %nin% operator?

Sometimes I write code like this:

> qf.a <- subset(qf, pubid %in% c(104, 106, 107, 108)) qf.b <- 
> subset(qf, !pubid %in% c(104, 106, 107, 108))

and I get a little worried that maybe I've remembered the precedence
rules wrong, so I change it to

> qf.a <- subset(qf, pubid %in% c(104, 106, 107, 108)) qf.b <- 
> subset(qf, !(pubid %in% c(104, 106, 107, 108)))

and pretty soon my code looks like fingernail clippings (or Lisp) and
I'm thinking about precedence rather than my original task.  So I write
a %nin% operator which I define as:

> `%nin%` <- function (x, table) match(x, table, nomatch = 0L) == 0L

and then I'm happy again.

I wonder, would something like this find a home in core R?  Or is that
too much syntactic sugar for your taste?

--
Ken Williams
Sr. Research Scientist
Thomson Reuters
Phone: 651-848-7712
ken.williams at thomsonreuters.com

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