dunder_methods.md

Dunder Mehtods

These two 'dunder' methods for classes allow you to change how you reper

The __str__ method returns a string output “ Paul, is 36 years old” instead of the object id in the memory, whenever we call the class. However, if you just inspect the object, you will still get the memory address.

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    # __str__ allows you to convert Python objects into strings
    def __str__(self):
        return f"{self.name}, is {self.age} years old"

    # __repr__ allows you to return unambiguous version of your class
    def __repr__(self):
        return f"<{self.name}, is {self.age} years old>"


paul = Person("Paul", 36)
print(paul)  # returns : Paul, is 36 years old

Another Example

import datetime

today = dataetime.date.today()

str(today) # '2021-02-22'
repr(today) # 'datetime.date(2021, 02, 22)

__str__ or str() is used for creating output that is human-readable are must be for end-users. But, repr() or __repr__ must serve the purpose of debugging and development