Count number of unique levels of a variable
The following should do the job:
choices <- length(unique(iris$Species))
If we are using dplyr
, n_distinct
would get the number of unique elements in each column
library(dplyr)
iris %>%
summarise_each(funs(n_distinct))
# Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#1 35 23 43 22 3
If your need is to count the number of unique instances for each column of your data.frame, you can use sapply
:
sapply(iris, function(x) length(unique(x)))
#### Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#### 35 23 43 22 3
For just one specific colum, the code suggested by @Imran Ali (in the comments) is perfectly fine.