Getting same output as cut() using speedier hist() or findInterval()?

Question

I read this article http://www.r-bloggers.com/comparing-hist-and-cut-r-functions/ and tested hist() to be faster than cut() by ~4 times on my PC. My sc

Answer 1

Here is an implementation based on your findInterval suggestion which is 5-6 times faster than classical cut:

cut2 <- function(x, breaks) {
  labels <- paste0("(",  breaks[-length(breaks)], ",", breaks[-1L], "]")
  return(factor(labels[findInterval(x, breaks)], levels=labels))
}

library(microbenchmark)

set.seed(1)
data <- rnorm(1e4, mean=0, sd=1)

microbenchmark(cut.default(data, my_breaks), cut2(data, my_breaks))

# Unit: microseconds
#                         expr      min        lq    median        uq      max neval
# cut.default(data, my_breaks) 3011.932 3031.1705 3046.5245 3075.3085 4119.147   100
#        cut2(data, my_breaks)  453.761  459.8045  464.0755  469.4605 1462.020   100

identical(cut(data, my_breaks), cut2(data, my_breaks))
# TRUE