duplicated()
determines which elements of a vector or data frame are duplicates
of elements with smaller subscripts, and returns a logical vector
indicating which elements (rows) are duplicates.
Usage
# S3 method for class 'integer64'
duplicated(x, incomparables = FALSE, nunique = NULL, method = NULL, ...)
Arguments
- x
a vector or a data frame or an array or
NULL
.- incomparables
ignored
- nunique
NULL or the number of unique values (including NA). Providing
nunique
can speed-up matching whenx
has no cache. Note that a wrongnunique
can cause undefined behaviour up to a crash.- method
NULL for automatic method selection or a suitable low-level method, see details
- ...
ignored
Value
duplicated()
: a logical vector of the same length as x
.
Details
This function automatically chooses from several low-level functions
considering the size of x
and the availability of a cache.
Suitable methods are
hashdup
(hashing)sortorderdup
(fast ordering)orderdup
(memory saving ordering).
Examples
x <- as.integer64(sample(c(rep(NA, 9), 1:9), 32, TRUE))
duplicated(x)
#> [1] FALSE FALSE FALSE FALSE TRUE TRUE TRUE TRUE FALSE TRUE FALSE
#> [12] TRUE TRUE TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE
#> [23] TRUE TRUE TRUE FALSE FALSE TRUE TRUE TRUE TRUE TRUE
stopifnot(identical(duplicated(x), duplicated(as.integer(x))))