bit: bit_sort_unique – R documentation

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bit

bit_sort_unique

bit sort unique

Description

fast combination of sort and unique for integers

Usage

bit_sort_unique(
  x,
  decreasing = FALSE,
  na.last = NA,
  has.dup = TRUE,
  range_na = NULL
)

Arguments

`x`	an integer vector
`decreasing`	`FALSE` (ascending) or `TRUE` (descending)
`na.last`	`NA` removes NAs, `FALSE` puts NAs at the beginning, `TRUE` puts NAs at the end
`has.dup`	TRUE (the default) assumes that `x` might have duplicates, set to `FALSE` if duplicates are impossible
`range_na`	`NULL` calls `range_na`, optionally the result of `range_na` can be given here to avoid calling it again

Details

determines the range of the integers and checks if the density justifies use of a bit vector; if yes, creates the result using a bit vector; if no, falls back to sort(unique())

Value

a sorted unique integer vector

Examples

bit_sort_unique(c(2L,1L,NA,NA,1L,2L))
bit_sort_unique(c(2L,1L,NA,NA,1L,2L), na.last=FALSE)
bit_sort_unique(c(2L,1L,NA,NA,1L,2L), na.last=TRUE)
bit_sort_unique(c(2L,1L,NA,NA,1L,2L), decreasing = TRUE)
bit_sort_unique(c(2L,1L,NA,NA,1L,2L), decreasing = TRUE, na.last=FALSE)
bit_sort_unique(c(2L,1L,NA,NA,1L,2L), decreasing = TRUE, na.last=TRUE)

## Not run: 
x <- sample(1e7, replace=TRUE)
system.time(bit_sort_unique(x))
system.time(sort(unique(x)))
x <- sample(1e7)
system.time(bit_sort_unique(x))
system.time(sort(x))

## End(Not run)

bit

Classes and Methods for Fast Memory-Efficient Boolean Selections

v4.0.4

GPL-2 | GPL-3

Authors

Jens Oehlschlägel [aut, cre], Brian Ripley [ctb]

Initial release

2020-08-03