n_distinct function

Count unique combinations

n_distinct() counts the number of unique/distinct combinations in a set of one or more vectors. It's a faster and more concise equivalent to nrow(unique(data.frame(...))).

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

Arguments

• ...: Unnamed vectors. If multiple vectors are supplied, then they should have the same length.
• na.rm: If TRUE, exclude missing observations from the count. If there are multiple vectors in ..., an observation will be excluded if any of the values are missing.

Returns

A single number.

Examples

x <- c(1, 1, 2, 2, 2)
n_distinct(x)

y <- c(3, 3, NA, 3, 3)
n_distinct(y)
n_distinct(y, na.rm = TRUE)

# Pairs (1, 3), (2, 3), and (2, NA) are distinct
n_distinct(x, y)

# (2, NA) is dropped, leaving 2 distinct combinations
n_distinct(x, y, na.rm = TRUE)

# Also works with data frames
n_distinct(data.frame(x, y))