bit64 (version 4.5.2)

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).

Arguments

x

a vector or a data frame or an array or NULL.

incomparables

ignored

order

The order in which unique values will be returned, see details

nunique

NULL or the number of unique values (including NA). Providing nunique can speed-up matching when x has no cache. Note that a wrong nunique can cause undefined behaviour up to a crash.

method

NULL for automatic method selection or a suitable low-level method, see details

...

ignored

Author

Jens Oehlschlägel <[e-mail]>

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) and 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.integer64 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))))