Message-ID: <f8e6ff050805021229l2c1b36c9kdf0ee276849646db@mail.gmail.com>
Date: 2008-05-02T19:29:55Z
From: Hadley Wickham
Subject: Out of bounds negative index
In-Reply-To: <DFD3645F-329A-4280-A256-4708B0D54503@act.ulaval.ca>
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
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