R dplyr: rename variables using string functions

Question

(Somewhat related question: Enter new column names as string in dplyr's rename function)

In the middle of a dplyr chain (%>%), I wou

Answer 1

Both select() and select_all() can be used to rename columns.

If you wanted to rename only specific columns you can use select:

iris %>% 
  select(sepal_length = Sepal.Length, sepal_width = Sepal.Width, everything()) %>% 
  head(2)

  sepal_length sepal_width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa

rename does the same thing, just without having to include everything():

iris %>% 
  rename(sepal_length = Sepal.Length, sepal_width = Sepal.Width) %>% 
  head(2)

  sepal_length sepal_width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa

select_all() works on all columns and can take a function as an argument:

iris %>% 
  select_all(tolower)

iris %>% 
  select_all(~gsub("\\.", "_", .)) 

or combining the two:

iris %>% 
  select_all(~gsub("\\.", "_", tolower(.))) %>% 
  head(2)

  sepal_length sepal_width petal_length petal_width species
1          5.1         3.5          1.4         0.2  setosa
2          4.9         3.0          1.4         0.2  setosa