Rename and recode range of new variables in dataframe in R - r

Question

I essentially want recode and rename a range of variables in a dataframe. I am looking for a way to do this in the single step.
Example in pseudo-code:
require(dplyr)
df <- iris %>% head()
df %>% mutate(
paste0("x", 1:3) = across( # In the example I want to rename
Sepal.Length:Petal.Length, # the variables I've selected
~ .x + 1 # and recoded to "x1" ... "x5"
)
)
df
Desired output:
x1 x2 x3 Petal.Width Species
<dbl> <dbl> <dbl> <dbl> <fct>
1 5.1 3.5 1.4 0.2 setosa
2 4.9 3.0 1.4 0.2 setosa
3 4.7 3.2 1.3 0.2 setosa
4 4.6 3.1 1.5 0.2 setosa
5 5.0 3.6 1.4 0.2 setosa
6 5.4 3.9 1.7 0.4 setosa

Answer 1

Maybe rename_with() is what you want. After that you can manipulate these renamed columns with mutate(across(...)).
library(dplyr)
df %>%
rename_with(~ paste0("x", seq_along(.x)), Sepal.Length:Petal.Length) %>%
mutate(across(x1:x3, ~ .x * 10))
x1 x2 x3 Petal.Width Species
1 51 35 14 0.2 setosa
2 49 30 14 0.2 setosa
3 47 32 13 0.2 setosa
4 46 31 15 0.2 setosa
5 50 36 14 0.2 setosa
6 54 39 17 0.4 setosa
If you want to manipulate and rename a range of columns in one step, try the argument .names in across().
df %>%
mutate(across(Sepal.Length:Petal.Length, ~ .x * 10,
.names = "x{seq_along(.col)}"),
.keep = "unused", .after = 1)
x1 x2 x3 Petal.Width Species
1 51 35 14 0.2 setosa
2 49 30 14 0.2 setosa
3 47 32 13 0.2 setosa
4 46 31 15 0.2 setosa
5 50 36 14 0.2 setosa
6 54 39 17 0.4 setosa
Hint: You can use seq_along() to create a sequence 1, 2, ... along with the selected columns, or match() to get the positions of the selected columns in the data, i.e. .names = "x{match(.col, names(df))}".

Answer 2

The below code allows you to just input the column numbers into a for loop, not sure if this is what you're going for.
require(dplyr)
df <- iris %>% head()
for(i in 1:3){
names(df)[i] <- paste0("x",i)
}
df
Outputs:
x1 x2 x3 Petal.Width Species
1 5.1 3.5 1.4 0.2 setosa
2 4.9 3.0 1.4 0.2 setosa
3 4.7 3.2 1.3 0.2 setosa
4 4.6 3.1 1.5 0.2 setosa
5 5.0 3.6 1.4 0.2 setosa
6 5.4 3.9 1.7 0.4 setosa

Answer 3

You could add consecutive numbers to n columns with the same prefix this way:
df <- iris %>% head()
n <- 3
colnames(df)[1:n] <- sprintf("x%s",1:n)
output:
# x1 x2 x3 Petal.Width Species
# 1 5.1 3.5 1.4 0.2 setosa
# 2 4.9 3.0 1.4 0.2 setosa
# 3 4.7 3.2 1.3 0.2 setosa
# 4 4.6 3.1 1.5 0.2 setosa
# 5 5.0 3.6 1.4 0.2 setosa
# 6 5.4 3.9 1.7 0.4 setosa
Of any nonconsecutive number of columns by:
n <- c(1,3,5)
colnames(df)[n] <- sprintf("x%s",n)
# x1 Sepal.Width x3 Petal.Width x5
# 1 5.1 3.5 1.4 0.2 setosa
# 2 4.9 3.0 1.4 0.2 setosa
# 3 4.7 3.2 1.3 0.2 setosa
# 4 4.6 3.1 1.5 0.2 setosa
# 5 5.0 3.6 1.4 0.2 setosa
# 6 5.4 3.9 1.7 0.4 setosa