counting-distincts

``` r
library(tidyverse)

iris %>% 
  count(Species)
#> # A tibble: 3 x 2
#>   Species        n
#>   <fct>      <int>
#> 1 setosa        50
#> 2 versicolor    50
#> 3 virginica     50

iris %>% 
  count(Species) %>% 
  count()
#> # A tibble: 1 x 1
#>       n
#>   <int>
#> 1     3

# can also name it
iris %>% 
  count(Species) %>% 
  count(name = "count_species")
#> # A tibble: 1 x 1
#>   count_species
#>           <int>
#> 1             3

# basically same as
iris %>% 
  distinct(Species) %>% 
  tally()
#>   n
#> 1 3

# can pull all of above, but no pull here!
# Thanks Michael Sumner
iris %>% 
  group_by(Species) %>% 
  n_groups()
#> [1] 3

# Thanks Nick Tierney
iris %>% 
  pull(Species) %>% 
  n_distinct()
#> [1] 3

# also works, need to pull
iris %>% 
  summarize(n_species = n_distinct(Species)) %>% 
  pull()
#> [1] 3
```

<sup>Created on 2019-07-16 by the [reprex package](https://reprex.tidyverse.org) (v0.2.1)</sup>