[FIXED] How do I fix this error, in my multiple class example?

Issue

class Students: #class is called Students
    
    def__init__(self, name, age, grade): #constructor for self, name, and age, for Students
    
    self.name = name
    self.age = age
    self.grade = grade
    
    def get_grade(self):
        
        return self.grade
    
class Course: #this class is called Course
    
    def__init__(self, name, max_students): #constructor to get name of Course and max number of students in Course
        
        self.name = name
        self.max_students = max_students
        self.students[]
    
    def add_student(self, student): #code to add students into course
        
        if len(self.students) < max_students:
            
            self.students.append(student) #if theres less students than the max number of students for Course, then append into course until it reaches max number of students
            return True
        return False
    
    def get_average_grade(self): #code to find the average
       pass

s1 = Student("Sam", 19, 78) #s1 is now accessing the Student class. Name, age and grade
s2 = Student("Bam", 19, 58)
s3 = Student("Pam", 19, 48)

course = Course("English", 2) #course is now accessing the Course class.Name of course and max number of students for course.
course.add_student(s1)
course.add_student(s2) #using add_student attribute in Course class to add students into course
print(course.add_student) #printing the result

image of the error I got

Please be detailed with your answers, since I am a beginner. Thanks.

What have I done wrong? How could i have been more efficient? And how can I prevent this error from happening?

Solution

There are multiple issues with your code:

1. Your class is called Students but you're initializing Student (missing the "s" at the end)

2. print(course.add_student) tries to print the method add_student() itself instead of what the method returns. You need to call the method with an argument: print(course.add_student(s1))

3. The add_student() method returns a boolean, so your print statement will print True. This is not technically incorrect, but maybe not what you want. if you want to see if the students have been added successfully you can instead for example check that the course now has two students: print(len(course.students))

4. Within your if statement in add_student() you need to compare to self.max_students, not to max_students

5. Within Course you are not initializing self.students correctly, you are missing the equal sign. It should be like this: self.students = []. This is what was causing your error message.

Here's a cleaned up version of your code:

class Students:
    def __init__(self, name, age, grade):
        self.name = name
        self.age = age
        self.grade = grade

    def get_grade(self):
        return self.grade

class Course: 
    def __init__(self, name, max_students):
        self.name = name
        self.max_students = max_students
        self.students = []

    def add_student(self, student): 
        if len(self.students) < self.max_students:
            self.students.append(student)
            return True
        return False

    def get_average_grade(self):
        pass

s1 = Students("Sam", 19, 78)
s2 = Students("Bam", 19, 58)
s3 = Students("Pam", 19, 48)

course = Course("English", 2)
print(len(course.students))  # You haven't added students yet, so this will print 0

result1 = course.add_student(s1)
result2 = course.add_student(s2)
result3 = course.add_student(s3) # This will be false and no student will be added since the max_student limit is exceeded

print(result1)
print(result2)
print(result3)

print(len(course.students)) # Now you have two students in your course

Answered By - Ada