search
HomeBackend DevelopmentPython TutorialCan You Override Python\'s Special Methods Directly on Instances?

Can You Override Python's Special Methods Directly on Instances?

Overriding Special Methods on Instance Objects

In Python, special methods with names surrounded by double underscores are typically not invoked on instances but rather on their classes. This is an implementation detail of CPython, the standard interpreter. Consequently, it is not possible to override __repr__() directly on an instance and expect the custom implementation to be used.

For instance, consider the following code:

class A(object):
    pass

def __repr__(self):
    return "A"

from types import MethodType
a = A()
print(a)   # Output: <__main__.a object at>
print(repr(a))  # Output: '<__main__.a object at>'</__main__.a></__main__.a>

As we can see, repr(a) does not yield the expected result of "A."

To work around this limitation, one must define a new method that calls the original implementation, as follows:

class A(object):
    def __repr__(self):
        return self._repr()
    def _repr(self):
        return object.__repr__(self)

Now, you can override __repr__() on an instance by replacing _repr():

setattr(a, "_repr", MethodType(my_repr, a, a.__class__))

where my_repr is the desired custom implementation.

The above is the detailed content of Can You Override Python\'s Special Methods Directly on Instances?. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How do NumPy arrays differ from the arrays created using the array module?How do NumPy arrays differ from the arrays created using the array module?Apr 24, 2025 pm 03:53 PM

NumPyarraysarebetterfornumericaloperationsandmulti-dimensionaldata,whilethearraymoduleissuitableforbasic,memory-efficientarrays.1)NumPyexcelsinperformanceandfunctionalityforlargedatasetsandcomplexoperations.2)Thearraymoduleismorememory-efficientandfa

How does the use of NumPy arrays compare to using the array module arrays in Python?How does the use of NumPy arrays compare to using the array module arrays in Python?Apr 24, 2025 pm 03:49 PM

NumPyarraysarebetterforheavynumericalcomputing,whilethearraymoduleismoresuitableformemory-constrainedprojectswithsimpledatatypes.1)NumPyarraysofferversatilityandperformanceforlargedatasetsandcomplexoperations.2)Thearraymoduleislightweightandmemory-ef

How does the ctypes module relate to arrays in Python?How does the ctypes module relate to arrays in Python?Apr 24, 2025 pm 03:45 PM

ctypesallowscreatingandmanipulatingC-stylearraysinPython.1)UsectypestointerfacewithClibrariesforperformance.2)CreateC-stylearraysfornumericalcomputations.3)PassarraystoCfunctionsforefficientoperations.However,becautiousofmemorymanagement,performanceo

Define 'array' and 'list' in the context of Python.Define 'array' and 'list' in the context of Python.Apr 24, 2025 pm 03:41 PM

InPython,a"list"isaversatile,mutablesequencethatcanholdmixeddatatypes,whilean"array"isamorememory-efficient,homogeneoussequencerequiringelementsofthesametype.1)Listsareidealfordiversedatastorageandmanipulationduetotheirflexibility

Is a Python list mutable or immutable? What about a Python array?Is a Python list mutable or immutable? What about a Python array?Apr 24, 2025 pm 03:37 PM

Pythonlistsandarraysarebothmutable.1)Listsareflexibleandsupportheterogeneousdatabutarelessmemory-efficient.2)Arraysaremorememory-efficientforhomogeneousdatabutlessversatile,requiringcorrecttypecodeusagetoavoiderrors.

Python vs. C  : Understanding the Key DifferencesPython vs. C : Understanding the Key DifferencesApr 21, 2025 am 12:18 AM

Python and C each have their own advantages, and the choice should be based on project requirements. 1) Python is suitable for rapid development and data processing due to its concise syntax and dynamic typing. 2)C is suitable for high performance and system programming due to its static typing and manual memory management.

Python vs. C  : Which Language to Choose for Your Project?Python vs. C : Which Language to Choose for Your Project?Apr 21, 2025 am 12:17 AM

Choosing Python or C depends on project requirements: 1) If you need rapid development, data processing and prototype design, choose Python; 2) If you need high performance, low latency and close hardware control, choose C.

Reaching Your Python Goals: The Power of 2 Hours DailyReaching Your Python Goals: The Power of 2 Hours DailyApr 20, 2025 am 12:21 AM

By investing 2 hours of Python learning every day, you can effectively improve your programming skills. 1. Learn new knowledge: read documents or watch tutorials. 2. Practice: Write code and complete exercises. 3. Review: Consolidate the content you have learned. 4. Project practice: Apply what you have learned in actual projects. Such a structured learning plan can help you systematically master Python and achieve career goals.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.