ifelse()
   get_help() docs


Description

The unique() function comes with R and is part of the Base R {base} package.

We use this function to extract all unique values from an array, i.e. remove all duplicates from an array.

Note that there is related function in the {dplyr} package called dplyr::distinct() which can be used to obtain distinct (aka, unique) rows from tibbles (data frames).

Conceptual Usage

unique(array to keep unique values of)

Examples

Some examples below use the carnivores dataset. Learn more about this dataset with get_help("carnivores").

# Show the carnivores dataset
carnivores
## # A tibble: 9 × 4
##   name              genus        awake brainwt
##   <chr>             <fct>        <dbl>   <dbl>
## 1 Arctic fox        Vulpes        11.5  0.0445
## 2 Cheetah           Acinonyx      11.9 NA     
## 3 Dog               Canis         13.9  0.07  
## 4 Gray seal         Haliochoerus  17.8  0.325 
## 5 Jaguar            Panthera      13.6  0.157 
## 6 Lion              Panthera      10.5 NA     
## 7 Northern fur seal Callorhinus   15.3 NA     
## 8 Red fox           Vulpes        14.2  0.0504
## 9 Tiger             Panthera       8.2 NA


# Keep only unique values in the given array (remove duplicates)
my_array <- c(1, 1, 3, 6, 6, 9, 12, 15, 15)
unique(my_array)
## [1]  1  3  6  9 12 15


# Show only the unique values in the carnivores variable `genus`
unique(carnivores$genus)
## [1] Vulpes       Acinonyx     Canis        Haliochoerus Panthera     Callorhinus 
## Levels: Acinonyx Callorhinus Canis Haliochoerus Panthera Vulpes