Private method access instance variable in R

In R programming language, we can access instance variables or class attributes, even inside a private method. However, we need to follow some specific rules to do it.

First, we need to define the private method inside the class using the setMethod() function with the private modifier. Next, to access the instance variable inside the private method, we need to use the @ symbol followed by the name of the instance variable.

Here is an example code that demonstrates how to access instance variables in a private method in R:

# Define a class with an instance variable and a private method
setClass("MyClass",
         slots = c(attr = "character"),
         private = list(
           my_private_method = function() {
             # Access the instance variable 'attr' using '@'
             cat("The attribute value is:", @attr, "\n")
           }
         )
)
# Create an object of MyClass

obj <- new("MyClass", attr = "my_value")
# Call the private method to access the instance variable

obj@my_private_method()

# Output: The attribute value is: my_value

In the above example, we have defined a MyClass with an instance variable called attr of type character and a private method called my_private_method. This private method accesses the instance variable using the @attr syntax.

Finally, we create an object of MyClass and call the private method using obj@my_private_method() to access the instance variable value.