wow =P
Thank you guys. I will use the hb2 , because it is the fastest one.
Eddie
> wow! :)
>
> vQ
>
> Henrik Bengtsson wrote:
> > library(gsubfn)
> > library(gtools)
> > library(rbenchmark)
> >
> > n <- 10000
> > df <- data.frame(
> > a = rnorm(n),
> > b = rnorm(n),
> > c = rnorm(n),
> > ip = replicate(n, paste(sample(255, 4), collapse='.'), simplify=TRUE)
> > )
> >
> > res <- benchmark(columns=c('test', 'elapsed'), replications=10,
> > order=NULL, peda = {
> > connection <- textConnection(as.character(df$ip))
> > o <- do.call(order, read.table(connection, sep='.'))
> > close(connection)
> > df[o, ]
> > },
> >
> > peda2 = {
> > connection <- textConnection(as.character(df$ip))
> > dfT <- read.table(connection, sep='.', colClasses=rep("integer",
> > 4), quote="", na.strings=NULL, blank.lines.skip=FALSE)
> > close(connection)
> > o <- do.call(order, dfT)
> > df[o, ]
> > },
> >
> > hb = {
> > ip <- strsplit(as.character(df$ip), split=".", fixed=TRUE)
> > ip <- unlist(ip, use.names=FALSE)
> > ip <- as.integer(ip)
> > dim(ip) <- c(4, nrow(df))
> > ip <- 256^3*ip[1,] + 256^2*ip[2,] + 256*ip[3,] + ip[4,]
> > o <- order(ip)
> > df[o, ]
> > },
> >
> > hb2 = {
> > ip <- strsplit(as.character(df$ip), split=".", fixed=TRUE)
> > ip <- unlist(ip, use.names=FALSE)
> > ip <- as.integer(ip);
> > dim(ip) <- c(4, nrow(df))
> > o <- sort.list(ip[4,], method="radix", na.last=TRUE)
> > for (kk in 3:1) {
> > o <- o[sort.list(ip[kk,o], method="radix", na.last=TRUE)]
> > }
> > df[o, ]
> > }
> > )
> >
> > print(res)
> >
> > test elapsed
> > 1 peda 4.12
> > 2 peda2 4.08
> > 3 hb 0.28
> > 4 hb2 0.25
>
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