How Can I Customize the String Representation of a Class in Python?

Customizing Class String Representation

In Python, classes are objects and thus have their own string representation. By default, this representation is . Designing custom representation for classes can be useful for debugging, logging, or other purposes.

To achieve this customization, a metaclass is employed. In Python, a metaclass is a class that creates other classes. By implementing the __str__ or __repr__ method in a metaclass, the string representation of the class can be customized.

The __str__ method provides a user-readable string representation, while __repr__ provides an unambiguous representation for development and debugging. Here's an example using __repr__:

class MC(type):
  def __repr__(self):
    return 'Wahaha!'

class C(object):
  __metaclass__ = MC

print(C)  # Prints 'Wahaha!'

In Python 3, the __metaclass__ attribute is replaced with a metaclass keyword argument. Here's the Python 3 version of the example:

class MC(type):
  def __repr__(self):
    return 'Wahaha!'

class C(object, metaclass=MC):
    pass

print(C)  # Prints 'Wahaha!'

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