Class inheritance and importing -- python

Question

This may be a little lengthy but I am at a loss with importing my parent and child class.

I have a feeling I am getting my capitalization incorrect when applying the class names. I am getting the error:

TypeError: Student.__init__() missing 2 required positional arguments: 'age' and 'major'

Any help is much appreciated.

StudentAdder.py (Main)

import pickle
from sre_constants import SUCCESS
from tkinter import *
from tkinter import messagebox
from student import Student
from person import Person

#main method
def main():

    studentList = []
    #load the list from a pickle file
    with open("student.pickle", "rb") as f:
        studentList = pickle.load(f)

    #addStudent method to append Input to list
    def addStudent():
        name = "name"
        age = "age"
        major = "major"
        name = nameInput.get()
        age = ageInput.get()
        major = majorInput.get()
        studentList.append(Student(name, age, major))
        #save list to pickle file
        with open("student.pickle", "wb") as f:
            pickle.dump(studentList, f)

    #displays a success message upon adding a student
    def onClick():
        messagebox.showinfo("SUCCESS", "Student Added!")

    #create a GUI
    window = Tk()
    window.title("Add a Student")
    window.geometry("325x175")
  
    #create labels and text boxes for each value
    nameLabel = Label(window, text="Name:")
    ageLabel = Label(window, text="Age:")
    majorLabel = Label(window, text="Major:")

    nameInput = StringVar()
    ageInput = StringVar()
    majorInput = StringVar()

    #create grid for labels
    nameLabel.grid(row=0, column=0)
    ageLabel.grid(row=1, column=0)
    majorLabel.grid(row=2, column=0)

    #create input boxes for each value
    nameInput = Entry(window, width = 25)
    ageInput = Entry(window, width = 25)
    majorInput = Entry(window, width = 25)

    #create grid for input boxes
    nameInput.grid(row=0, column=1)
    ageInput.grid(row=1, column=1)
    majorInput.grid(row=2, column=1)

    #create a save button to save the student -- binds commands to button
    saveButton = Button(window, text="Save", command= lambda: [addStudent(), onClick()])
    saveButton.grid(row=3, column=1)

    #create quit button
    quitButton = Button(window, text="Quit", command= window.destroy)
    quitButton.grid(row=4, column=1)

    #start the GUI
    window.mainloop()

    #print the list
    print()
    for student in studentList:
        print(student)

    print()

main()

person.py (Parent Class)

#create a parent class
class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def getName(self):
        return self.name

    def getAge(self):
        return self.age

    def setName(self, name):
        self.name = name

    def setAge(self, age):
        self.age = age

    def __str__(self):
        return "Person: " + self.name + " " + str(self.age)

student.py (Child Class)

from person import Person

class Student(Person):
    def __init__(self, name, age, major):
        Student(Person).__init__(self, name, age, major)
        self.name = name
        self.age = age
        self.major = major

    def getMajor(self):
        return self.major

    def setMajor(self, major):
        self.major = major

    def __str__(self):
        return "Student: " + self.name + \
            ", Age: " + str(self.age) + \
            ", Major: " + self.major

Why are you calling Student(Person).__init__(self, name, age, major) inside Student.__init__? You probably want to call super().__init__(name, age) and then self.major = major. — Mark
– Mark, Commented Apr 10, 2022 at 3:34

Jack Taylor · Accepted Answer · 2022-04-10 03:36:54Z

3

It looks like your mistake is this line in student.py:

Student(Person).__init__(self, name, age, major)

The code Student(Person) is trying to make a new instance of Student, but you are only passing one argument (Person) instead of the required three (name, age and major). That is why you see missing 2 required positional arguments: 'age' and 'major' in your error message.

However, it looks like you are actually trying to call the __init__ method of the parent class. You would do that like this:

super().__init__(name, age)

Note that I did not specify the major argument, as the Person class does not accept this as a parameter. Also, the __init__ method of the Person class already stores the name and age parameters, so you don't need to do that in Student.__init__. So you can change Student.__init__ to be the following:

class Student(Person):
    def __init__(self, name, age, major):
        super().__init__(name, age)
        self.major = major

Alternatively, if you don't want to depend on Person.__init__, you can leave out the super() call and set all the attributes yourself:

class Student(Person):
    def __init__(self, name, age, major):
        self.name = name
        self.age = age
        self.major = major

answered Apr 10, 2022 at 3:36

Jack Taylor

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6 Comments

Nicholas Renard Over a year ago

Thank you for the quick reply. I did make the changes you suggested super().__init__(name, age) but I'm still seeing the TypeError. Maybe studentList.append(Student(name, age, major)) is an issue? Or is that correct?

Jack Taylor Over a year ago

That part looks correct to me. Maybe you didn't save the file, or you are running an old version of the code, or something like that?

Nicholas Renard Over a year ago

Oh god... you're right. All good. Thank you again!

Jack Taylor Over a year ago

Also, is the error message exactly the same, or is it slightly different? It's possible you may have a similar-looking but slightly different problem.

Jack Taylor Over a year ago

Ok, all good. Nice!

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