Inheritance from parent class not working: superclass init call not correctly? [closed]-CodePudding

I have the following code:

class Person:
    species="human"
    def __init__(self, fname, lname):
        self.firstname=fname
        self.lastname=lname

person_1=Person("Mike", "Smithfield")
person_2=Person("Sara", "Smithfield")

print(person_1.species)
print(person_1.firstname)
print(person_1.lastname)

class Teacher(Person):
    typeof="School teacher"
    def __init__(self, fname, lname, schoolgrade):
        Person.__init__(self, fname, lname)
        self.schoolclass=schoolgrade

teacher_1=Teacher("John", "Dire", "first grade")

print(teacher_1.species)
print(teacher_1.typeof)
print(teacher_1.fname)
print(teacher_1.lname)
print(teacher_1.schoolclass)

When running it I get the error message:

AttributeError: 'Teacher' object has no attribute 'fname'

Obviously the inheritance of firstname and lastname did not work. I thought that

Person.__init__(self, fname, lname)

means that when I call this from the Teacher class, so I call the init of the parent person class, the teacher will inherit the (instance) attritube firstname and lastname. So with calling:

teacher_1=Teacher("John", "Dire", "first grade")

It should work, but it doesn't?

CodePudding user response：

You are storing the argument under a different name:

self.firstname=fname

Change code to:

print(teacher_1.firstname)
print(teacher_1.lastname)

same as when you printed for person_1

CodePudding user response：

The attribute name is firstname, the parameter is named fname. If you want to access the attribute, the syntax is teacher_1.firstname

CodePudding user response：

An easy way to deal with such classes is using dataclass.

It will save you the boilerplate you need to implement when you write such classes.

from dataclasses import dataclass

@dataclass
class Person:
    firstname :str
    lasrname:str

@dataclass
class Teacher(Person):
  schoolclass:str

person: Person = Person('Jack','Smith')
print(person)

teacher: Teacher = Teacher('Jack','Smith','first grade')
print(teacher)

output

Person(firstname='Jack', lasrname='Smith')
Teacher(firstname='Jack', lasrname='Smith', schoolclass='first grade')