[R] Numeric "Label" of Factor value?

Sarah Goslee
2012-10-10T18:48:28Z

Hi Brigid,

as.numeric() extracts the index of the factor level, which is the way
R handles the likelihood that a factor is not actually numeric. Try:

> as.numeric(as.character(abc[1]))
[1] 2

and see also ?factor particularly the section on the interpretation of a factor.

Sarah

On Wed, Oct 10, 2012 at 2:39 PM, Brigid Mooney <bkmooney at gmail.com>
wrote:
> Sorry, I'm sure I'm not using the appropriate vocab here, which is
> undoubtedly why I can't seem to find a fix to this (hopefully very
> easy) problem.
>
> Suppose you have a factor
>
> abc <- factor(c(2,2,3,4,7,7))
>
> And you want to know what the number in the nth spot in that would be
>
> abc[1]
> [1] 2
> Levels: 2 3 4 7
>
> shows the correct label of the first element - but if I want to pull
> out the numeric value of that label, I thought...
>
> as.numeric(abc[1])
>
> but that gives
> [1] 1
>
> which is the position of the label in the levels vector of the factor.
>
> Ideas?
>
> Thanks!
>
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--
Sarah Goslee