• vec_duplicate_any(): detects the presence of duplicated values, similar to anyDuplicated().

  • vec_duplicate_detect(): returns a logical vector describing if each element of the vector is duplicated elsewhere. Unlike duplicated(), it reports all duplicated values, not just the second and subsequent repetitions.

  • vec_duplicate_id(): returns an integer vector giving the location of the first occurence of the value.

vec_duplicate_any(x)

vec_duplicate_detect(x)

vec_duplicate_id(x)

Arguments

x

A vector (including a data frame).

Value

  • vec_duplicate_any(): a logical vector of length 1.

  • vec_duplicate_detect(): a logical vector the same length as x.

  • vec_duplicate_id(): an integer vector the same length as x.

Missing values

In most cases, missing values are not considered to be equal, i.e. NA == NA is not TRUE. This behaviour would be unappealing here, so these functions consider all NAs to be equal. (Similarly, all NaN are also considered to be equal.)

Performance

These functions are currently slightly slower than their base equivalents. This is primarily because they do a little more checking and coercion in R, which makes them both a little safer and more generic. Additionally, the C code underlying vctrs has not yet been implemented: we expect some performance improvements when that happens.

See also

vec_unique() for functions that work with the dual of duplicated values: unique values.

Examples

vec_duplicate_any(1:10)
#> [1] FALSE
vec_duplicate_any(c(1, 1:10))
#> [1] TRUE
x <- c(10, 10, 20, 30, 30, 40) vec_duplicate_detect(x)
#> [1] TRUE TRUE FALSE TRUE TRUE FALSE
# Note that `duplicated()` doesn't consider the first instance to # be a duplicate duplicated(x)
#> [1] FALSE TRUE FALSE FALSE TRUE FALSE
# Identify elements of a vector by the location of the first element that # they're equal to: vec_duplicate_id(x)
#> [1] 1 1 3 4 4 6
# Location of the unique values: vec_unique_loc(x)
#> [1] 1 3 4 6
# Equivalent to `duplicated()`: vec_duplicate_id(x) == seq_along(x)
#> [1] TRUE FALSE TRUE TRUE FALSE TRUE