In my Student subclass below, I am calculating average GPA from manually inputted grades stored in the self.courses
dict attribute as {course:grade}.
The user should be able to enter in the console >>>print(fred.gpa),given fred is a proper Student instance with grades in self.courses
, and should get 3.8
(for example) printed to the console.
However, 3.8
does not print to console, rather <bound method Student.gpa of <college.Student object at 0x7ff55e122ad0>>
I understand that this is the result of printing a function, but I want to print just a number using just print(fred.gpa) and not fred.gpa()
Does this mean I have to convert the output of gpa.Student into a string?
Here is my code for ref:
def __init__(self, name, cid, email):
self.courses = {}
super().__init__(name, cid, email)
def add_course(self, course):
if course in self.courses:
# duplicate courses not allowed
raise ValueError
print("student is already registered for this course")
else:
self.courses.update({course:0})
return self
def update_grade(self, course, grade):
if course not in self.courses:
# student must be registered in class to receive grade
raise ValueError
print("student is not registered for this course")
else:
self.courses[course] = float(grade)
return self
def gpa(self):
grades = list(self.courses.values())
totGPA = sum(grades)/len(grades)
return str(totGPA)
What you need is something that will let you implement something as a method, but access it as a non-method attribute. That turns out to be quite easy - it's called a property
, and it works like this:
class Student:
@property
def gpa(self):
# Rest of the implementation, unchanged
Ta-da!
Note that you can fix up your implementation of gpa
a little: sum
can take any iterable (it doesn't have to be a list), and dicts (and their keys
, values
and items
views) have a length, so you can do:
@property
def gpa(self):
return sum(self.courses.values())/len(self.courses)
I've omitted your call to str
, since it seems from your question that that was a first attempt to fix your problem. You could reinstate it if you need it there for some other reason.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.