[R] Power functions?

Stavros Macrakis macrakis at alum.mit.edu
Sat Jan 3 22:52:10 CET 2009


Watch the operator precedences.  In R (and many other languages)

    -1^2 == -(1^2) == -1

Perhaps you intended:

    (-1)^2 == 1

On Sat, Jan 3, 2009 at 3:32 PM,  <rkevinburton at charter.net> wrote:
> I had a question about the basic power functions in R.
>
> For example from the R console I enter:
>
> -1 ^ 2
> [1] -1
>
> but also
>
> -1^3
> [1] -1
>
> -0.1^2
> [1]  -0.01
>
> Normally pow(-1, 2) return either -Infinity or NaN. Has R taken over the math functions? If so I would think that -1^2 is 1 not -1 and -0.1^2 is 0.01 not -0.01.
>
> Thank you.
>
> Kevin
>
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