In this tutorial, we will learn how to sort columns of a dataframe in alphabetical order. We will first use tidyverse to sort columns of a dataframe using two different ways. And then we will see how to use base R functions to sort the columns.
Let us load tidyverse.
library(tidyverse)
We will use starwars that is built-in with dplyr package. Let us look at the column names of starwars dataframe.
starwars %>% colnames() [1] "name" "height" "mass" "hair_color" "skin_color" [6] "eye_color" "birth_year" "sex" "gender" "homeworld" [11] "species" "films" "vehicles" "starships"
Sorting columns with tidyverse
Using order() function on the column names we can order the column names in alphabatical order. This gives us a vector with ordered column names and we can use select() function from dplyr to select the ordered columns
starwars %>%
select(order(colnames(.)))
# A tibble: 87 × 14
birth_year eye_color films gender hair_color height homeworld mass name
<dbl> <chr> <list> <chr> <chr> <int> <chr> <dbl> <chr>
1 19 blue <chr [5]> mascu… blond 172 Tatooine 77 Luke…
2 112 yellow <chr [6]> mascu… <NA> 167 Tatooine 75 C-3PO
3 33 red <chr [7]> mascu… <NA> 96 Naboo 32 R2-D2
4 41.9 yellow <chr [4]> mascu… none 202 Tatooine 136 Dart…
5 19 brown <chr [5]> femin… brown 150 Alderaan 49 Leia…
6 52 blue <chr [3]> mascu… brown, gr… 178 Tatooine 120 Owen…
7 47 blue <chr [3]> femin… brown 165 Tatooine 75 Beru…
8 NA red <chr [1]> mascu… <NA> 97 Tatooine 32 R5-D4
9 24 brown <chr [1]> mascu… black 183 Tatooine 84 Bigg…
10 57 blue-gray <chr [6]> mascu… auburn, w… 182 Stewjon 77 Obi-…
# … with 77 more rows, and 5 more variables: sex <chr>, skin_color <chr>,
# species <chr>, starships <list>, vehicles <list>
We can see that after ordering the column names are alphabetical order.
starwars %>% select(order(colnames(.))) %>% colnames() [1] "birth_year" "eye_color" "films" "gender" "hair_color" [6] "height" "homeworld" "mass" "name" "sex" [11] "skin_color" "species" "starships" "vehicles"
Sorting columns using tidyselect’s peek_vars()
Another approach to sort columns using tidyverse is to use tidyselect’s peek_vars() function with sort() function as shown below.
starwars %>% select(sort(tidyselect::peek_vars())) %>% colnames() [1] "birth_year" "eye_color" "films" "gender" "hair_color" [6] "height" "homeworld" "mass" "name" "sex" [11] "skin_color" "species" "starships" "vehicles"
Sorting columns using base R
We can also sort the columns using base R funntions alone. Here we use order() function on the column names and use [] to select the ordered columns.
starwars[, order(colnames(starwars))]
# A tibble: 87 × 14
birth_year eye_color films gender hair_color height homeworld mass name
<dbl> <chr> <list> <chr> <chr> <int> <chr> <dbl> <chr>
1 19 blue <chr [5]> mascu… blond 172 Tatooine 77 Luke…
2 112 yellow <chr [6]> mascu… <NA> 167 Tatooine 75 C-3PO
3 33 red <chr [7]> mascu… <NA> 96 Naboo 32 R2-D2
4 41.9 yellow <chr [4]> mascu… none 202 Tatooine 136 Dart…
5 19 brown <chr [5]> femin… brown 150 Alderaan 49 Leia…
6 52 blue <chr [3]> mascu… brown, gr… 178 Tatooine 120 Owen…
7 47 blue <chr [3]> femin… brown 165 Tatooine 75 Beru…
8 NA red <chr [1]> mascu… <NA> 97 Tatooine 32 R5-D4
9 24 brown <chr [1]> mascu… black 183 Tatooine 84 Bigg…
10 57 blue-gray <chr [6]> mascu… auburn, w… 182 Stewjon 77 Obi-…
# … with 77 more rows, and 5 more variables: sex <chr>, skin_color <chr>,
# species <chr>, starships <list>, vehicles <list>
starwars[, order(colnames(starwars))] %>% colnames() [1] "birth_year" "eye_color" "films" "gender" "hair_color" [6] "height" "homeworld" "mass" "name" "sex" [11] "skin_color" "species" "starships" "vehicles"
https://stackoverflow.com/questions/29873293/dply-order-columns-alphabetically-in-r