What is the purpose of `__repr__` in Python and how does it differ from `__str__`?

Unveiling the Representer: Exploring the Enigma of repr

Python's vast ecosystem of object-oriented prowess is adorned by a multifaceted family of dunder methods, each meticulously designed to cater to specific needs. Among this pantheon resides the enigmatic __repr__, a mystical entity shrouded in mystery and crucial to the realm of object representation.

Consider yourself an intrepid investigator tasked with unraveling the enigma of __repr__. Your quest begins with an examination of its anatomy, as exemplified by the intricate code snippet presented:

<code class="python">def __repr__(self):
  return '<%s %s (%s:%s) %s>' % (
    self.__class__.__name__, self.urlconf_name, self.app_name,
    self.namespace, self.regex.pattern)</code>

The cryptic syntax of repr conceals a profound purpose. It empowers objects with the ability to articulate a discernible representation of their inner self, a portrayal that distills their essence into a legible format. This representation transcends the mere confines of visual appeal; it serves as a blueprint for recreating the object, allowing it to be resurrected from its symbolic incarnation.

The significance of repr extends beyond its role as a resuscitator. It is the chosen conduit for presenting objects within interactive shells, interactive playgrounds for programmers to tinker and explore. By overriding __repr__, you wield the power to customize how your objects are depicted, transforming them from enigmatic entities into comprehensible companions.

However, the responsibilities of repr end where str__'s reign begins. Whereas __repr prioritizes developer-friendly representations, str assumes the mantle of catering to end-users. It seeks to craft a representation that resonates with human sensibilities, an interpretation that paints a clear and concise picture.

To illustrate the nuanced distinction, consider the following code snippet:

<code class="python">class Point:
    def __init__(self, x, y):
        self.x, self.y = x, y
    def __repr__(self):
        cls = self.__class__.__name__
        return f'{cls}(x={self.x!r}, y={self.y!r})'</code>

Invoking repr yields an output tailored for developers:

>>> p = Point(1, 2)
>>> print(repr(p))
Point(x=1, y=2)  # Developer-centric representation

In contrast, str produces a more user-friendly rendition:

>>> print(str(p))
(1, 2)  # User-friendly representation

Thus, repr emerges as an indispensable tool for crafting bespoke object representations, an instrument for debugging and introspection. It unveils the inner workings of objects, demystifying their complexities and facilitating their resurrection. Its companion, __str__, assumes the role of translator, rendering objects in a form that aligns with human understanding. Together, these dunder methods orchestrate the vibrant tapestry of Python's object representation, empowering developers to interact with objects in both informative and user-friendly ways.

The above is the detailed content of What is the purpose of `__repr__` in Python and how does it differ from `__str__`?. For more information, please follow other related articles on the PHP Chinese website!