bit64 (version 4.8.4)

unique.integer64: Extract Unique Elements from integer64

Description

unique returns a vector like x but with duplicate elements/rows removed.

Usage

# S3 method for integer64
unique(
  x,
  incomparables = FALSE,
  order = c("original", "values", "any"),
  nunique = NULL,
  method = NULL,
  ...
)

Value

For a vector, an object of the same type of x, but with only one copy of each duplicated element. No attributes are copied (so the result has no names).

Details

This function automatically chooses from several low-level functions considering the size of x and the availability of a cache.

Suitable methods are

• hashmapuni (simultaneously creating and using a hashmap)

• hashuni (first creating a hashmap then using it)

• sortuni (fast sorting for sorted order only)

• sortorderuni (fast ordering for original order only)

• orderuni (memory saving ordering).

The default order="original" returns unique values in the order of the first appearance in x like in unique(), this costs extra processing. order="values" returns unique values in sorted order like in table(), this costs extra processing with the hash methods but comes for free. order="any" returns unique values in undefined order, possibly faster. For hash methods this will be a quasi random order, for sort methods this will be sorted order.

See Also

unique() for the generic, unipos() which gives the indices of the unique elements and table() which gives frequencies of the unique elements.

Examples

x <- as.integer64(sample(c(rep(NA, 9), 1:9), 32, TRUE))
unique(x)
unique(x, order="values")

stopifnot(identical(unique(x),  x[!duplicated(x)]))
stopifnot(identical(unique(x),  as.integer64(unique(as.integer(x)))))
stopifnot(identical(unique(x, order="values")
,  as.integer64(sort(unique(as.integer(x)), na.last=FALSE))))