R: Find and count unique values

vec_unique {vctrs} | R Documentation

## Find and count unique values

### Description

- `vec_unique()`: the unique values. Equivalent to `unique()`.

- `vec_unique_loc()`: the locations of the unique values.

- `vec_unique_count()`: the number of unique values.

### Usage

    vec_unique(x)

    vec_unique_loc(x)

    vec_unique_count(x)

### Arguments

`x` | A vector (including a data frame).

### Value

- `vec_unique()`: a vector the same type as `x` containing only unique values.

- `vec_unique_loc()`: an integer vector, giving locations of unique values.

- `vec_unique_count()`: an integer vector of length 1, giving the number of unique values.

### 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.)

### See Also

vec_duplicate for functions that work with the dual of unique values: duplicated values.

### Examples

    x <- rpois(100, 8)
    vec_unique(x)
    vec_unique_loc(x)
    vec_unique_count(x)

    # `vec_unique()` returns values in the order that encounters them
    # use sort = "location" to match to the result of `vec_count()`
    head(vec_unique(x))
    head(vec_count(x, sort = "location"))

    # Normally missing values are not considered to be equal
    NA == NA

    # But they are for the purposes of considering uniqueness
    vec_unique(c(NA, NA, NA, NA, 1, 2, 1))

[Package vctrs version 0.2.2 Index]