In R, a private method is a method that can only be accessed within the object it belongs to and cannot be accessed outside of the object.
To create a private method in R, we use the <<- assignment operator instead of the usual <- operator. This makes the method a part of the object and inaccessible outside of it.
Here is an example:
# Define a Student class with a private method 'print_details'
Student <- function(name, age, gender) {
details <- list(
name = name,
age = age,
gender = gender
)
# Define print_details as a private method
details$print_details <<- function() {
cat("Name:", details$name, "\n")
cat("Age:", details$age, "\n")
cat("Gender:", details$gender, "\n")
}
return(details)
}
# Create a student object
s1 <- Student("John", 25, "Male")
# Try to access print_details outside of the object (returns an error)
s1$print_details()
# Access print_details within the object
s1$print_details()
In the above example, we define a
Student class that has a private method print_details which is only accessible within the Student object. We use the <<- operator to define print_details as a private method, thereby making it inaccessible outside of the Student object.
When we try to access print_details outside of the object s1, it returns an error message. However, we can access it within the object by calling s1$print_details(), which prints the student's name, age, and gender.