Вы можете создать столбец Week
из date
и фильтр для max(Week)
library(data.table)
#> Warning: package 'data.table' was built under R version 3.6.2
testset <- data.table(date=as.Date(c("2013-07-02","2013-08-03","2013-09-04",
"2013-10-05","2013-11-06")),
yr = c(2013,2013,2013,2013,2013),
mo = c(07,08,09,10,11),
da = c(02,03,04,05,06),
plant = LETTERS[1:5],
product = as.factor(letters[26:22]),
rating = runif(25))
testset$Week <- format(testset$date, "%W")
testset[Week == max(Week)]
#> date yr mo da plant product rating Week
#> 1: 2013-11-06 2013 11 6 E v 0.7794414 44
#> 2: 2013-11-06 2013 11 6 E v 0.4971975 44
#> 3: 2013-11-06 2013 11 6 E v 0.6272580 44
#> 4: 2013-11-06 2013 11 6 E v 0.3748460 44
#> 5: 2013-11-06 2013 11 6 E v 0.6683196 44