Dunder or magic methods in Python
Dunder or magic methods in Python are the methods having two prefix and suffix underscores in the method name. Dunder here means “Double Under (Underscores)”. These are commonly used for operator overloading. Few examples for magic methods are:
__init__, __add__, __len__, __repr__ etc.
__init__ method for initialization is invoked without any call, when an instance of a class is created, like constructors in certain other programming languages such as C++, Java, C#, PHP etc. These methods are the reason we can add two strings with ‘+’ operator without any explicit typecasting.
Here’s a simple implementation :
<__main__.String object at 0x7fe992215390>
The above snippet of code prints only the memory address of the string object. Let’s add a
__repr__ method to represent our object.
If we try to add a string to it :
TypeError: unsupported operand type(s) for +: 'String' and 'str'
__add__ method to String class :
Reference : docs.python.org.