From deepayan.sarkar at gmail.com  Fri Jun  4 12:10:10 2010
From: deepayan.sarkar at gmail.com (Deepayan Sarkar)
Date: Fri, 4 Jun 2010 15:40:10 +0530
Subject: [Rd] Argument recycling in substring()
In-Reply-To: <19464.52085.361753.726627@lynne.math.ethz.ch>
References: <4C084E8D.4000002@fhcrc.org>
	<19464.52085.361753.726627@lynne.math.ethz.ch>
Message-ID: <AANLkTim3FDCsrgi3rMJ2WeQy_BbiWRDyLXFgjQFc3z7f@mail.gmail.com>

2010/6/4 Martin Maechler <maechler at stat.math.ethz.ch>:
>>>>>> "HP" == Herv? Pag?s <hpages at fhcrc.org>
>>>>>> ? ? on Thu, 03 Jun 2010 17:53:33 -0700 writes:
>
> ? ?HP> Hi,
> ? ?HP> According to its man page substring() "expands (its) arguments
> ? ?HP> cyclically to the length of the longest _provided_ none are of
> ? ?HP> zero length".
>
> ? ?HP> So, as expected, I get an error here:
>
> ? ?>> substring("abcd", first=2L, last=integer(0))
> ? ?HP> Error in substring("abcd", first = 2L, last = integer(0)) :
> ? ?HP> invalid substring argument(s)
>
> ? ?HP> But I don't get one here:
>
> ? ?>> substring(character(0), first=1:2, last=3L)
> ? ?HP> character(0)
>
> ? ?HP> which is unexpected.
> according to the docu.
>
> My gut feeling would say that the documentation should be
> updated in this case, rather than the implementation.
>
> RFC! other opinions?

I agree. The current behaviour is reasonable.

-Deepayan



[Rd] Argument recycling in substring()
Deepayan Sarkar