Peter Dalgaard wrote:
> 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,]
>
>
here's another:
library(gsubfn)
a[order(gsubfn(
'[0-9]+',
~ sprintf('%03d', as.integer(x)),
as.character(a$ip))),]
vQ
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