The goal of factor256 is to minimize the memory footprint of data analysis that uses categorical variables with fewer than 256 unique values.
You can install the development version of factor256 from GitHub with:
# install.packages("devtools")
devtools::install_github("HughParsonage/factor256")This is a basic example which shows you how to solve a common problem:
library(factor256)
x <- factor256(LETTERS)
typeof(x)
#> [1] "raw"
identical(recompose256(x), LETTERS)
#> [1] TRUElibrary(data.table)
DT <-
CJ(Year = 2000:2020,
State = rep_len(c("WA", "SA", "NSW", "NT", "TAS", "VIC", "QLD"), 1000),
Age = rep_len(0:100, 10000))
# pryr::object_size(DT)
# 3.36GB
for (j in seq_along(DT)) {
set(DT, j = j, value = factor256(.subset2(DT, j)))
}
# pryr::object_size(DT)
# 630 MB