[R] sort a data frame according to roman characters

Peter Dalgaard P.Dalgaard at biostat.ku.dk
Tue Feb 12 12:04:37 CET 2008


Luis Ridao Cruz wrote:
> R-help,
>
> I have a data frame with one column containing roman numbers
> The data are not sorted as : I    II   III  IV   V    VI   VII  VIII IX
>   X    XI   XII  XIII XIV  XV
>
> Using data[order(data$Roman),] does not do the job.
>
> How can this be done?
>
>   

Someone went there before you (and me):

library(utils)
data[order(as.roman(data$Roman)),]

(possibly ....as.character(data$Roman).... if it has been read as a factor)

-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
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