Hi Peter,
This works as I expected. Thank you very much.
Eddie
> Date: Fri, 29 May 2009 11:15:37 +0200
> From: p.dalga...@biostat.ku.dk
> To: all...@cybaea.com
> CC: r-help@r-project.org
> Subject: Re: [R] IP-Address
>
> Allan Engelhardt wrote:
> > IP addresses are very (very!) difficult to parse and sort correctly
> > because there are all sorts of supported formats. Try to use something
> > like PostgreSQL instead: it is already implemented there. But if you
> > are sure all your data is of the n.n.n.n form, then something along the
> > lines of the following should basically work (I have chosen some more
> > interesting IP addresses for this):
> >
> >
> > a <- data.frame(cbind(id=c(138,138,138,138),
> > rank=c(29746,29746,29746,29746),
> > color=c("yellow","red","blue","red"),
> > status=c("no","yes","yes","no"),
> >
> > ip=c("162.131.58.26","2.131.58.16","2.2.58.10","162.131.58.17")))
> > a
> > # id rank color status ip
> > # 1 138 29746 yellow no 162.131.58.26
> > # 2 138 29746 red yes 2.131.58.16
> > # 3 138 29746 blue yes 2.2.58.10
> > # 4 138 29746 red no 162.131.58.17
> > x <- matrix(unlist(lapply(strsplit(as.character(a$ip), ".", fixed=TRUE),
> > as.integer)),
> > ncol=4, byrow=TRUE)
> > a[order(x[,1],x[,2],x[,3],x[,4]),]
> > # id rank color status ip
> > # 3 138 29746 blue yes 2.2.58.10
> > # 2 138 29746 red yes 2.131.58.16
> > # 4 138 29746 red no 162.131.58.17
> > # 1 138 29746 yellow no 162.131.58.26
> >
> >
> > Getting rid of the conversions including the matrix(unlist) combo is
> > left as an exercise (it's too hot here....)
>
> Here's one way:
>
> con <- textConnection(as.character(a$ip))
> o <- do.call(order,read.table(con,sep="."))
> close(con)
> a[o,]
>
>
> --
> O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
> c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
> (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
> ~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907
>
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