vctrs: vec_count – R documentation

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vec_count

Count unique values in a vector

Description

Count the number of unique values in a vector. vec_count() has two important differences to table(): it returns a data frame, and when given multiple inputs (as a data frame), it only counts combinations that appear in the input.

Usage

vec_count(x, sort = c("count", "key", "location", "none"))

Arguments

x

A vector (including a data frame).

sort

One of "count", "key", "location", or "none".

"count", the default, puts most frequent values at top
"key", orders by the output key column (i.e. unique values of x)
"location", orders by location where key first seen. This is useful if you want to match the counts up to other unique/duplicated functions.
"none", leaves unordered.

Value

A data frame with columns key (same type as x) and count (an integer vector).

Dependencies

Examples

vec_count(mtcars$vs)
vec_count(iris$Species)

# If you count a data frame you'll get a data frame
# column in the output
str(vec_count(mtcars[c("vs", "am")]))

# Sorting ---------------------------------------

x <- letters[rpois(100, 6)]
# default is to sort by frequency
vec_count(x)

# by can sort by key
vec_count(x, sort = "key")

# or location of first value
vec_count(x, sort = "location")
head(x)

# or not at all
vec_count(x, sort = "none")

vctrs

Vector Helpers

v0.3.8

MIT + file LICENSE

Authors

Hadley Wickham [aut], Lionel Henry [aut, cre], Davis Vaughan [aut], data.table team [cph] (Radix sort based on data.table's forder() and their contribution to R's order()), RStudio [cph]

Initial release