Count

The function count() counts the number of each unique value within one or more variables.

Dataset

For demonstration we’ll load the amphibian_div_tbl data from the mgrtibbles package (hyperlink includes install instructions).

#Load package
library("mgrtibbles")
#amphibian_div_tbl tibble for demonstration
mgrtibbles::amphibian_div_tbl

# A tibble: 138 × 15
   Species                  IUCN.Red.List.Status iucn_2cat Order   Family  Genus
   <chr>                    <fct>                <fct>     <chr>   <chr>   <chr>
 1 Acris blanchardi         <NA>                 <NA>      Anura   Hylidae Acris
 2 Acris crepitans          Least Concern (LC)   LC        Anura   Hylidae Acris
 3 Acris gryllus            Least Concern (LC)   LC        Anura   Hylidae Acris
 4 Ambystoma barbouri       Near Threatened (NT) nonLC     Caudata Ambyst… Amby…
 5 Ambystoma jeffersonianum Least Concern (LC)   LC        Caudata Ambyst… Amby…
 6 Ambystoma laterale       Least Concern (LC)   LC        Caudata Ambyst… Amby…
 7 Ambystoma macrodactylum  Least Concern (LC)   LC        Caudata Ambyst… Amby…
 8 Ambystoma maculatum      Least Concern (LC)   LC        Caudata Ambyst… Amby…
 9 Ambystoma texanum        Least Concern (LC)   LC        Caudata Ambyst… Amby…
10 Ambystoma tigrinum       Least Concern (LC)   LC        Caudata Ambyst… Amby…
# ℹ 128 more rows
# ℹ 9 more variables: Age_at_maturity_min_y <dbl>, Age_at_maturity_max_y <dbl>,
#   Body_size_mm <dbl>, Longevity_max_y <dbl>, Litter_size_min_n <dbl>,
#   Litter_size_max_n <dbl>, Offspring_size_min_mm <dbl>,
#   Offspring_size_max_mm <fct>, Development <chr>

One variable/column

The count() function will count the number of each unique value within one or more variables.

amphibian_div_tbl |> dplyr::count(IUCN.Red.List.Status)

# A tibble: 7 × 2
  IUCN.Red.List.Status                 n
  <fct>                            <int>
1 Least Concern (LC)                  94
2 Near Threatened (NT)                12
3 Data Deficient (DD)                  8
4 Vulnerable (VU)                     18
5 Endangered (EN)                      4
6 Least Concern (LC) - Provisional     1
7 <NA>                                 1

The count() function works on grouped tibbles, counting the unique values within the group.

amphibian_div_tbl |> 
    #Group by IUCN.Red.List.Status
    dplyr::group_by(IUCN.Red.List.Status) |>
    #Count will count grouped info
    dplyr::count()

# A tibble: 7 × 2
# Groups:   IUCN.Red.List.Status [7]
  IUCN.Red.List.Status                 n
  <fct>                            <int>
1 Least Concern (LC)                  94
2 Near Threatened (NT)                12
3 Data Deficient (DD)                  8
4 Vulnerable (VU)                     18
5 Endangered (EN)                      4
6 Least Concern (LC) - Provisional     1
7 <NA>                                 1

Multiple variables/columns

It also works when specifying multiple variables/columns to use together.

amphibian_div_tbl |> dplyr::count(Order, Family, Genus)

# A tibble: 26 × 4
   Order   Family         Genus          n
   <chr>   <chr>          <chr>      <int>
 1 Anura   Ascaphidae     Ascaphus       2
 2 Anura   Bufonidae      Anaxyrus       4
 3 Anura   Bufonidae      Incilius       1
 4 Anura   Hylidae        Acris          3
 5 Anura   Hylidae        Hyla           7
 6 Anura   Hylidae        Pseudacris     6
 7 Anura   Ranidae        Rana          14
 8 Anura   Scaphiopodidae Spea           2
 9 Caudata Ambystomatidae Ambystoma      7
10 Caudata Amphiumidae    Amphiuma       3
# ℹ 16 more rows