Sample code:
library(tidyverse)
iris <- iris
test_tidyeval <- function(data, col_name, col_name_2, column1) {
mutate(
data,
{{col_name}} := case_when(Species == "setosa" ~ column1 + Sepal.Width + Petal.Length,
TRUE ~ column1),
{{col_name_2}} := case_when(Species == "setosa" ~ {{col_name}} + 100,
TRUE ~ {{col_name}} + 500))
}
iris %>% test_tidyeval("new_column_test", "new_column_test_2", Sepal.Length)
I'm sure this is a tidyeval/nse issue which I can never get my head around.
What I basically want is for new_column_test to be created where if the row Species == "setosa" then for this to be the sum of Sepal.Length, which we're passing to column1 in the user-defined function, Sepal.Width and Petal.length, else just return the value from Sepal.Length, then for new_column_test_2 to add 100 to new_column_test with the same logical condition used previously and 500 to non setosa species.
I can seem to manipulate the LHS of case_when okay but I'm stuck on the RHS statements.
You need to be careful when mixing strings and symbols. They behave differently. You use {{ }} when working with symbols and .data[[]] when working with strings. This should work
test_tidyeval <- function(data, col_name, col_name_2, column1) {
mutate(
data,
"{col_name}" := case_when(Species == "setosa" ~ {{column1}} + Sepal.Width + Petal.Length,
TRUE ~ {{column1}}),
"{col_name_2}":= case_when(Species == "setosa" ~ .data[[col_name]] + 100,
TRUE ~ .data[[col_name]] + 500))
}
iris %>% test_tidyeval("new_column_test", "new_column_test_2", Sepal.Length) %>% str()
#'data.frame': 150 obs. of 7 variables:
# $ Sepal.Length : num 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
# $ Sepal.Width : num 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
# $ Petal.Length : num 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
# $ Petal.Width : num 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
# $ Species : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
# $ new_column_test : num 10 9.3 9.2 9.2 10 11 9.4 9.9 8.7 9.5 ...
# $ new_column_test_2: num 110 109 109 109 110 ...
If you passed everything as symbols, it would look like this
test_tidyeval <- function(data, col_name, col_name_2, column1) {
mutate(
data,
"{{col_name}}" := case_when(Species == "setosa" ~ {{column1}} + Sepal.Width + Petal.Length,
TRUE ~ {{column1}}),
"{{col_name_2}}":= case_when(Species == "setosa" ~ {{col_name}} + 100,
TRUE ~ {{col_name}} + 500))
}
iris %>% test_tidyeval(new_column_test, new_column_test_2, Sepal.Length)