Efficiently count the number of unique values in a set of vector

This is a faster and more concise equivalent of length(unique(x))

n_distinct(..., na.rm = FALSE)

Arguments

...	vectors of values
na.rm	if TRUE missing values don't count

Examples

x <- sample(1:10, 1e5, rep = TRUE)
length(unique(x))
#> [1] 10
n_distinct(x)
#> [1] 10