[R] factor to real - best way to convert

[Gabor Grothendieck]

You can use as.is = TRUE arg to read.xls to get character
data rather than factors.

On 5/3/06, Knut Krueger <Knut-krueger at einthal.de> wrote:
> I have got  factor from read.xls:
>  > is(factor_value)
> [1] "factor"   "oldClass"
>
> ....
> [288] -0.32   0.18    0.18    0.18    -0.32   0.18    0.68
> [295] 0.68    0.18
> 43 Levels: -0.05 -0.13 -0.15 -0.18 -0.20 -0.26 ... 1.33
>
> If I am using the funciton as.real(factor_value)
>
> I get
> ............
> [271] 17 17  8 22  8  8 17 17 17 17 17 17 17 17 23  7 35  7
> [289] 23 23 23  7 23 35 35 23
>
> So I used as.real(as.matrix(factor_value))
> The result is as expected:
> [271]    NA    NA -0.35  0.15 -0.35 -0.35    NA    NA    NA
> [280]    NA    NA    NA    NA    NA  0.18 -0.32  0.68 -0.32
> [289]  0.18  0.18  0.18 -0.32  0.18  0.68  0.68  0.18
>
> Ok I found the way to convert with try and error, but I do not understand the way
> -------------------------------------------------------------
> and I found the hint in the fullref_manual:
>
> x<- as.numeric(levels(factor_value))[factor_value])
>
> Ok much better, but I would not be able to find the way from the
> ?as.numeric help page.
>
> Both versions are complete struggled in my mind.
>
> maybe anybody is albe to write some hints for me.
>
>
>
> with regards
> Knut
>
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