repr

repr is a built-in Python function that returns a string representation of an object. The string is intended to be unambiguous and, when feasible, could be used to recreate the object. This contrasts with str(), which aims for a readable, user-facing display.

The representation is produced by the object's __repr__ method. If a class does not define __repr__, the default implementation inherited from object returns a string like <ClassName object at 0x...>, which includes the memory address. Developers can customize this representation by defining __repr__ in their classes, typically returning a string that resembles the code needed to recreate the object (for example, Point(1, 2)).

Examples show typical behavior: repr(42) yields '42'; repr('hello') yields "'hello'"; repr([1, 2, 3]) yields '[1, 2, 3]'. For strings, non-printable characters are escaped. In the interactive Python interpreter, the value shown for an object uses repr by default.

Notes and limitations: repr is not guaranteed to be a valid Python expression for all objects, especially for complex or private state. Some objects may display implementation details or omitted information. If both __repr__ and __str__ are defined, repr(obj) uses __repr__ and str(obj) uses __str__.

Relation to formatting: repr is often used for debugging and logging, while user-facing messages typically rely on str() or explicit formatting. Understanding __repr__ helps in debugging and in creating readable, reconstructible representations of objects.