IP-Address

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