Learning to Cook
The third argument to R6Class()
is called public
and holds the user-facing functionality for the object. This argument should be a list, with names for each of its elements.
The public
element of an R6 class contains the functionality available to the user. Usually it will only contain functions.
The updated pattern for creating an R6 class generator is as follows:
thing_factory <- R6Class(
"Thing",
private = list(
a_field = "a value",
another_field = 123
),
public = list(
do_something = function(x, y, z) {
# Do something here
}
)
)
This exercise is part of the course
Object-Oriented Programming with S3 and R6 in R
Exercise instructions
A microwave oven factory has been partially defined for you.
- Update the
public
element of the definition to include acook
method.- The
cook
method is a function. - It should have one argument named
time_seconds
to denote the cooking time. - In the body of the
cook
method, you should passtime_seconds
toSys.sleep()
(docs), which does nothing for the allotted amount of time. - Finally, the
cook
method shouldprint()
(docs) the string"Your food is cooked!"
- The
- Create a microwave oven object called
a_microwave_oven
using themicrowave_oven_factory
'snew()
method. - Call
a_microwave_oven
'scook()
method, for 1 second.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Add a cook method to the factory definition
microwave_oven_factory <- R6Class(
"MicrowaveOven",
private = list(
power_rating_watts = 800
),
public = list(
___ = ___(___) {
___
___
}
)
)
# Create microwave oven object
a_microwave_oven <- ___
# Call cook method for 1 second
___