Python · Theory

Magic methods

Theory

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Magic methods

Magic methods (dunders) start and end with __. __init__ constructs. __str__ is print(). __len__ is len(obj). They hook your class into Python’s built-in syntax.

Write one — class Student with __str__ returning the name. print(s) should show Asha, not <__main__.Student>.

Magic methods — output — Asha. __str__ is what print uses. Without it you would see <Student object>.

Exam tip

Name three dunders and what built-in they power.

Example

# Magic methods
class Student:
    def __init__(self, name):
        self.name = name
    def __str__(self):
        return self.name
print(Student("Asha"))

Magic methods — output: Asha. __str__ is what print uses. Without it you would see <Student object>.

Short notes

Def__name__ methods hook built-ins.
Rule__init__ / __str__ / __len__ first.
Rememberprint uses __str__.

Python · Theory

Magic methods

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Theory

95/268

Magic methods

Magic methods (dunders) start and end with __. __init__ constructs. __str__ is print(). __len__ is len(obj). They hook your class into Python’s built-in syntax.

Write one — class Student with __str__ returning the name. print(s) should show Asha, not <__main__.Student>.

Magic methods — output — Asha. __str__ is what print uses. Without it you would see <Student object>.

Exam tip

Name three dunders and what built-in they power.

Example

# Magic methods
class Student:
    def __init__(self, name):
        self.name = name
    def __str__(self):
        return self.name
print(Student("Asha"))

Magic methods — output: Asha. __str__ is what print uses. Without it you would see <Student object>.

Short notes

Def__name__ methods hook built-ins.
Rule__init__ / __str__ / __len__ first.
Rememberprint uses __str__.

Magic methods

Example

Short notes

Questions

Magic methods

Example

Short notes

Questions