From h.wickham at gmail.com  Fri May  2 21:29:55 2008
From: h.wickham at gmail.com (hadley wickham)
Date: Fri, 2 May 2008 14:29:55 -0500
Subject: [Rd] Out of bounds negative index
In-Reply-To: <DFD3645F-329A-4280-A256-4708B0D54503@act.ulaval.ca>
References: <DFD3645F-329A-4280-A256-4708B0D54503@act.ulaval.ca>
Message-ID: <f8e6ff050805021229l2c1b36c9kdf0ee276849646db@mail.gmail.com>

On Fri, May 2, 2008 at 2:23 PM, Vincent Goulet
<vincent.goulet at act.ulaval.ca> wrote:
> Hi,
>
>  From the R Language Definition, Section 3.4.1:
>
>  "If i is positive and exceeds length(x) then the corresponding selection is
> NA. A negative out of bounds value for i causes an error."
>
>  (This is also mentioned in S Programming, footnote of page 24.)
>
>  Can someone please provide an example triggering the error? Looking in
> src/main/subscript.c I could not find exception handling for |i| >
> length(x), unless the negative subscript is mixed with NAs. In other cases,
> out of bounds negative indexes just seem silently ignored.
>
>  Did I missed or misinterpreted something, here?

Well, there's this:

> a <- 1:10
> a[NA]
 [1] NA NA NA NA NA NA NA NA NA NA
> a[-NA]
[1] NA


Hadley

-- 
http://had.co.nz/



[Rd] Out of bounds negative index
hadley wickham