Python Magic Methods
What are Magic Methods?
Magic methods are special methods whose names start and end with double underscores, like __init__() and __str__(). Because of the double underscores, they are also called dunder methods (short for "double underscore").
You do not call magic methods directly. Python calls them for you, automatically, in certain situations - like when an object is created, printed, or compared to another object.
Example
__init__() and __str__() are both magic methods:
class Person:
def __init__(self, name):
self.name = name
def __str__(self):
return f"Person: {self.name}"
p1 = Person("Emil")
print(p1)
Try it Yourself »
Note: __init__() runs automatically when an object is created, and __str__() runs automatically when the object is printed.
List of Magic Methods
This tutorial covers the following magic methods. Click a method to see a full lesson with examples:
| Method | Called By | Description |
|---|---|---|
__init__() | Person(...) | Runs when a new object is created |
__str__() | print(obj), str(obj) | Controls the readable text shown for an object |
__repr__() | repr(obj) | Controls the developer-facing representation |
__eq__() | obj1 == obj2 | Controls what "equal" means for the class |
__add__() | obj1 + obj2 | Controls what the + operator does |
__len__() | len(obj) | Returns the "length" of an object |
__lt__() | obj1 < obj2 | Controls how objects are ordered when compared or sorted |
__contains__() | item in obj | Controls what the in operator checks |
__call__() | obj(...) | Lets an object be called like a function |
Note: __init__() already has its own lesson in the Classes/Objects section.
