Special method
A special method is a Python method with a conventionally reserved name that defines an object's behavior for language operations or built-in functions.
The Quick Python Book, Fourth Edition
A special method is a Python method with a conventionally reserved name that defines object behavior for language operations or built-in functions.
- How it is used
- Lets user-defined classes respond to Python operations and built-in functions through familiar syntax.
- How deep it goes
- Works through __str__ and indexed access and assignment, while noting that full list emulation needs additional methods.
- Examples
- Uses a printable RGB color, a type-checked list, and a file-backed line reader to show different operation choices.
- What you can do after
- Build it from scratch by defining methods for printing or indexed access and assignment in a user-defined class.
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Get Programming: Learn to code with Python
A special method is a Python method with a predefined double-underscore name that is invoked implicitly by language syntax or explicitly as a regular method.
- How it is used
- Customizes user-defined classes so operators, printing, and object creation work through familiar Python notation.
- How deep it goes
- Explains naming, implementation, examples, errors, and equivalent calls, stopping short of a complete catalog of special methods.
- Examples
- Uses Fraction arithmetic, printed fractions, and suggested Circle and Stack string representations.
- What you can do after
- Build it from scratch by adding operator and string-display behavior to custom classes and rewriting shorthand calls explicitly.
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Python How-To
A special method is a Python method with a language-defined naming convention and protocol role, commonly using double underscores to control built-in object behavior.
- How it is used
- Uses protocol methods to customize representations, construction, call syntax, attribute lookup, and other built-in object behavior.
- How deep it goes
- Explains overriding with concrete __str__, __repr__, __call__, and __getattr__ examples, while noting that attribute resolution is simplified.
- Examples
- Demonstrates custom representations, a class-based timing decorator, boilerplate data classes, and cached profile-data lookup.
- What you can do after
- Build it from scratch by overriding protocol methods that make custom objects printable, callable, constructible, or lazily populated.
Related concepts
- __str__includes · __str__ is a Python special method that returns an object's informal, human-readable string representation.
- constructor methodincludes · A constructor is a type-associated operation or callable that creates or initializes an instance and establishes its initial state.
- classconfigures · A class is a programming-language construct that defines a type’s structure or behavior and provides a basis for creating or representing objects.
- __repr__includes · __repr__ is a Python special method that returns an object’s developer-oriented string representation, ideally unambiguous and suitable for recreating an equivalent object.
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