[R] warning message

[Simon Knapp]

The second and third arguments to ifelse are evaluated for all
elements of x (producing your warnings), then the appropriate elements
of each result are combined based on the (logical) values of the first
argument to ifelse.

On Tue, Oct 16, 2012 at 10:08 AM, Shi, Tao <shidaxia at yahoo.com> wrote:
> Hi list,
>
> Can somebody explain why there are these warning messages?  I just don't get it.  I'm using R 2.15.1 on WinXP.
>
> Thanks!
>
> Tao
>
>
>> x
> [1] -2.143510 -1.157450 -1.315581  1.033562 -1.225440 -1.179909
>
>>  ifelse(x>0, log2(x), -log2(-x))
> [1] -1.099975 -0.210950 -0.395700  0.047625 -0.293300 -0.238675
> Warning messages:
> 1: In ifelse(x > 0, log2(x), -log2(-x)) : NaNs produced
> 2: In ifelse(x > 0, log2(x), -log2(-x)) : NaNs produced
>
>
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