How to make the Python str() function work with a custom class?

Question

Often, when using a Python Package, I find myself using the str() function to convert a package's custom data-type to a string. If I were to try and create a Python Class for a module, how would I add compatibility to str() function for my package's class? example:

class Person:
  def __init__(self, name, age, likes, dislikes):
    self.name = name
    self.personality = {
      "likes": likes,
      "dislikes": dislikes
}

bill = Person("bill", 21, ["coding", "etc"], ["interviews", "socialising"])
strBill = str(bill) # This will store: '<__main__.Person object at 0x7fa68c2acac8>' but I want a dictionary containing all of the variables stored in this 'bill' class


print(strBill)

Implement [`__str__`](https://docs.python.org/3/reference/datamodel.html#object.__str__). — 0x5453, Jun 17 '21 at 18:46
Does this answer your question? [How to create a custom string representation for a class object?](https://stackoverflow.com/questions/4932438/how-to-create-a-custom-string-representation-for-a-class-object) — Pranav Hosangadi, Jun 17 '21 at 18:50

score 0 · Accepted Answer · answered Jun 17 '21 at 19:48

def __str__(self): will be used when you try to str(my_object). It would also be called in string interpolation such as f'This is my object: {my_object}'

def __repr__(self): will be used to represent your object in a console

>>> class A():
...     def __str__(self):
...             return 'im a string nicely formatted'
...     def __repr__(self):
...             return 'class A object'
...
>>> a = A()
>>> print(a)
im a string nicely formatted
>>> a
class A object

How to make the Python str() function work with a custom class?

1 Answers1