[R] factor issue
Dimitris Rizopoulos
d.rizopoulos at erasmusmc.nl
Thu Apr 30 14:14:33 CEST 2009
check the following:
http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-convert-factors-to-numeric_003f
Best,
Dimitris
Nattu wrote:
> Hi,
>
> I have a column which I have to convert from factors to numeric. I am using
> the command as.numeric(variable) to do this. But when I convert the numeric
> value becomes different from factor . for example.
>
>> class(B)
> [1] "factor"
>> B
> [1] 180 <NA> 183 175 163 155 <NA> 188 191 160 170 165 152 170
> 165
> [16] 163 160 163 165 <NA>
>> as.numeric(B)
> [1] 46 NA 47 42 30 26 NA 49 50 29 37 32 24 37 32 30 29 30 32 NA
> Is there a different way to convert factor to respective number ?
>
>
> also when i try to unclass it i get following output
>
>> unclass(B)
> [1] 46 NA 47 42 30 26 NA 49 50 29 37 32 24 37 32 30 29 30 32 NA
> attr(,"levels")
> [1] "102" "104" "107" "109" "110" "112" "114" "117" "119" "122" "124" "125"
> [13] "127" "129" "130" "132" "135" "137" "140" "142" "145" "147" "150" "152"
> [25] "153" "155" "157" "159" "160" "163" "164" "165" "166" "167" "168" "169"
> [37] "170" "171" "172" "173" "174" "175" "177" "178" "179" "180" "183" "185"
> [49] "188" "191" "193" "196" "198" "201" "203" "211" "46" "48" "51" "56"
> [61] "58" "60" "61" "63" "64" "65" "66" "69" "71" "74" "76" "79"
> [73] "81" "84" "86" "89" "91" "94" "97" "99" "U"
>
> Any help will be appreciated.
>
> Thanks a lot.
> Regards,
> Nataraju
> GM
>
--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center
Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
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