Bert,
> Turns out that there's an even faster alternative.
hah, but i'm *not* surprised. thanks for sharing the (current)
low-price leader!
and, thanks, again, to Kimmo for posting such a productive question!
cheers, Greg
----
my apply
user system elapsed
8.465 0.103 8.578
Bert's !duplicated
user system elapsed
2.397 0.000 2.399
Bert's x[,2]>x[,1]
user system elapsed
1.068 0.000 1.069
Bert's table()-based user system elapsed
0.235 0.000 0.235
my a.d.f(unique(cbind(do.call)))
user system elapsed
4.470 0.000 4.475
Eric Berger's unique(...pmin...pmax)
user system elapsed
0.820 0.017 0.837
Eric Berger's transmuting tibble...
user system elapsed
0.936 0.000 0.938
Kimmo Elo's [OP] mutating paste
user system elapsed
50.769 0.000 50.821
Rui Barradas' sort-based
user system elapsed
42.001 0.053 42.112
----
----
n <- 1000
x <- expand.grid(Source = 1:n, Target = 1:n)
cat("my apply\n")
system.time({
y <- apply(x, 1, function(y) return (c(A=min(y), B=max(y))))
unique(t(y))})
# user system elapsed
# 5.075 0.034 5.109
cat("Bert's !duplicated\n")
system.time({
x[!duplicated(cbind(do.call(pmin, x), do.call(pmax, x))), ]
})
# user system elapsed
# 1.340 0.013 1.353
# Still more efficient and still returning a data frame is:
cat("Bert's x[,2]>x[,1]\n")
system.time({
w <- x[, 2] > x[,1]
x[w, ] <- x[w, 2:1]
unique(x)})
# user system elapsed
# 0.693 0.011 0.703
cat("Bert's table()-based")
f <- function(x){
w <- x[,2] > x[,1]
x[w, ] <- x[w, 2:1]
x$counts <- as.vector(table(x)) ## drop the dim
x[x$counts>0, ]
}
system.time({
f(x)
})
cat("my a.d.f(unique(cbind(do.call)))\n")
system.time({
as.data.frame(unique(cbind(A=do.call(pmin,x), B=do.call(pmax,x))))
})
cat("Eric Berger's unique(...pmin...pmax)\n")
system.time({
unique(data.frame(V1=pmin(x$Source,x$Target), V2=pmax(x$Source,x$Target)))
})
cat("Eric Berger's transmuting tibble...\n")
require(dplyr)
xt<-tibble(x)
system.time({
xt %>% transmute( a=pmin(Source,Target), b=pmax(Source,Target)) %>%
unique() %>% rename(Source=a, Target=b)
})
cat("Kimmo Elo's [OP] mutating paste\n")
system.time({
xt %>%
mutate(pair=mapply(function(x,y)
paste0(sort(c(x,y)),collapse="-"), Source, Target)) %>%
distinct(pair,
.keep_all = T) %>%
mutate(Source=sapply(pair, function(x)
unlist(strsplit(x, split="-"))[1]), Target=sapply(pair, function(x)
unlist(strsplit(x, split="-"))[2])) %>%
select(-pair)
})
cat("Rui Barradas' sort-based\n")
system.time({
apply(x, 1, sort) |> t() |> unique()
})
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