DSC 20 Lecture 24

Source: https://docs.google.com/presentation/d/1vRgHqvw7YxlADO_tKuuNWONEkH1onKFwYxtCT9kFCcU/edit#slide=id.p1 (cont.)

Special Methods

Special Method Names in Python

__init__: Method invoked automatically when an object is constructed
__repr__: Method invoked to display an object as a Python expression
__add__: Method invoked to add one object to another
__bool__: Method invoked to convert an object to True or False
__float__: Method invoked to convert an object to a float (real number)

Implementing str and repr

Implementing str and repr

The behavior of str is complicated:

• An instance attribute called __str__ is ignored
• If no __str__ attribute is found, uses repr string
• By the way, str is a class, not a function
  • When you call str, you call a constructor for the built-in string type called str