एक अन्य बेंचमार्क जिसके परिणामस्वरूप आधार का उपयोग strsplitकिया जा सकता है, वर्तमान में एक स्तंभ में अलग-अलग पंक्तियों में अल्पविराम से अलग तारों को विभाजित करने की सिफारिश की जा सकती है , क्योंकि यह आकारों की एक विस्तृत श्रृंखला में सबसे तेज़ था:
s <- strsplit(v$director, ",", fixed=TRUE)
s <- data.frame(director=unlist(s), AB=rep(v$AB, lengths(s)))
ध्यान दें कि उपयोग करने fixed=TRUEका समय पर महत्वपूर्ण प्रभाव पड़ता है।
तुलना के तरीके:
met <- alist(base = {s <- strsplit(v$director, ",") #Matthew Lundberg
s <- data.frame(director=unlist(s), AB=rep(v$AB, sapply(s, FUN=length)))}
, baseLength = {s <- strsplit(v$director, ",") #Rich Scriven
s <- data.frame(director=unlist(s), AB=rep(v$AB, lengths(s)))}
, baseLeFix = {s <- strsplit(v$director, ",", fixed=TRUE)
s <- data.frame(director=unlist(s), AB=rep(v$AB, lengths(s)))}
, cSplit = s <- cSplit(v, "director", ",", direction = "long") #A5C1D2H2I1M1N2O1R2T1
, dt = s <- setDT(v)[, lapply(.SD, function(x) unlist(tstrsplit(x, "," #Jaap
, fixed=TRUE))), by = AB][!is.na(director)]
#, dt2 = s <- setDT(v)[, strsplit(director, "," #Jaap #Only Unique
# , fixed=TRUE), by = .(AB, director)][,.(director = V1, AB)]
, dplyr = {s <- v %>% #Jaap
mutate(director = strsplit(director, ",", fixed=TRUE)) %>%
unnest(director)}
, tidyr = s <- separate_rows(v, director, sep = ",") #Jaap
, stack = s <- stack(setNames(strsplit(v$director, ",", fixed=TRUE), v$AB)) #Jaap
#, dt3 = {s <- setDT(v)[, strsplit(director, ",", fixed=TRUE), #Uwe #Only Unique
# by = .(AB, director)][, director := NULL][, setnames(.SD, "V1", "director")]}
, dt4 = {s <- setDT(v)[, .(director = unlist(strsplit(director, "," #Uwe
, fixed = TRUE))), by = .(AB)]}
, dt5 = {s <- vT[, .(director = unlist(strsplit(director, "," #Uwe
, fixed = TRUE))), by = .(AB)]}
)
पुस्तकालय:
library(microbenchmark)
library(splitstackshape) #cSplit
library(data.table) #dt, dt2, dt3, dt4
#setDTthreads(1) #Looks like it has here minor effect
library(dplyr) #dplyr
library(tidyr) #dplyr, tidyr
डेटा:
v0 <- data.frame(director = c("Aaron Blaise,Bob Walker", "Akira Kurosawa",
"Alan J. Pakula", "Alan Parker", "Alejandro Amenabar", "Alejandro Gonzalez Inarritu",
"Alejandro Gonzalez Inarritu,Benicio Del Toro", "Alejandro González Iñárritu",
"Alex Proyas", "Alexander Hall", "Alfonso Cuaron", "Alfred Hitchcock",
"Anatole Litvak", "Andrew Adamson,Marilyn Fox", "Andrew Dominik",
"Andrew Stanton", "Andrew Stanton,Lee Unkrich", "Angelina Jolie,John Stevenson",
"Anne Fontaine", "Anthony Harvey"), AB = c('A', 'B', 'A', 'A', 'B', 'B', 'B', 'A', 'B', 'A', 'B', 'A', 'A', 'B', 'B', 'B', 'B', 'B', 'B', 'A'))
गणना और समय परिणाम:
n <- 10^(0:5)
x <- lapply(n, function(n) {v <- v0[rep(seq_len(nrow(v0)), n),]
vT <- setDT(v)
ti <- min(100, max(3, 1e4/n))
microbenchmark(list = met, times = ti, control=list(order="block"))})
y <- do.call(cbind, lapply(x, function(y) aggregate(time ~ expr, y, median)))
y <- cbind(y[1], y[-1][c(TRUE, FALSE)])
y[-1] <- y[-1] / 1e6 #ms
names(y)[-1] <- paste("n:", n * nrow(v0))
y #Time in ms
# expr n: 20 n: 200 n: 2000 n: 20000 n: 2e+05 n: 2e+06
#1 base 0.2989945 0.6002820 4.8751170 46.270246 455.89578 4508.1646
#2 baseLength 0.2754675 0.5278900 3.8066300 37.131410 442.96475 3066.8275
#3 baseLeFix 0.2160340 0.2424550 0.6674545 4.745179 52.11997 555.8610
#4 cSplit 1.7350820 2.5329525 11.6978975 99.060448 1053.53698 11338.9942
#5 dt 0.7777790 0.8420540 1.6112620 8.724586 114.22840 1037.9405
#6 dplyr 6.2425970 7.9942780 35.1920280 334.924354 4589.99796 38187.5967
#7 tidyr 4.0323765 4.5933730 14.7568235 119.790239 1294.26959 11764.1592
#8 stack 0.2931135 0.4672095 2.2264155 22.426373 289.44488 2145.8174
#9 dt4 0.5822910 0.6414900 1.2214470 6.816942 70.20041 787.9639
#10 dt5 0.5015235 0.5621240 1.1329110 6.625901 82.80803 636.1899
नोट, तरीके जैसे
(v <- rbind(v0[1:2,], v0[1,]))
# director AB
#1 Aaron Blaise,Bob Walker A
#2 Akira Kurosawa B
#3 Aaron Blaise,Bob Walker A
setDT(v)[, strsplit(director, "," #Jaap #Only Unique
, fixed=TRUE), by = .(AB, director)][,.(director = V1, AB)]
# director AB
#1: Aaron Blaise A
#2: Bob Walker A
#3: Akira Kurosawa B
निर्देशक केstrsplit लिए वापसी और इसके साथ तुलना की जा सकती हैunique
tmp <- unique(v)
s <- strsplit(tmp$director, ",", fixed=TRUE)
s <- data.frame(director=unlist(s), AB=rep(tmp$AB, lengths(s)))
लेकिन मेरी समझ में, यह नहीं पूछा गया था।
