th 341 - Python's Double Underscore Mystery: The What and Why [Duplicate]

Python’s Double Underscore Mystery: The What and Why [Duplicate]

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th?q=Why Does Python Use Two Underscores For Certain Things? [Duplicate] - Python's Double Underscore Mystery: The What and Why [Duplicate]

Python is a fascinating programming language with a lot of unique features. One such feature that has left many developers scratching their heads is the double underscore mystery. What exactly are those two underscores before and after a method or attribute? And more importantly, why are they used?

If you’ve ever seen a piece of Python code with double underscores, you’re not alone in wondering what they mean. These seemingly cryptic symbols are known as dunder methods, short for double underscore. Dunder methods in Python provide special methods for manipulating classes and instances, but they can be hard to understand at first glance.

So what makes dunder methods so important in Python? Understanding how they work can help you write cleaner and more efficient code. In this article, we’ll explore the what and why behind Python’s double underscore mystery. From __init__ to __repr__, we’ll dive deep into Python’s unique approach to object-oriented programming, and show you how you can use dunder methods to build more powerful and flexible Python programs.

Whether you’re a beginner just starting out with Python or an experienced developer looking to master the nuances of the language, this article is for you. Through clear explanations and practical examples, we’ll guide you through the world of dunder methods in Python, helping you unlock their full potential along the way. So buckle up and get ready to solve the double underscore mystery once and for all!

th?q=Why%20Does%20Python%20Use%20Two%20Underscores%20For%20Certain%20Things%3F%20%5BDuplicate%5D - Python's Double Underscore Mystery: The What and Why [Duplicate]
“Why Does Python Use Two Underscores For Certain Things? [Duplicate]” ~ bbaz

Comparison Blog Article: Python’s Double Underscore Mystery: The What and Why [Duplicate]

The Basics of Python’s Double Underscore

The use of double underscores, also known as dunder, is a unique feature of Python. In essence, this feature implies that these particular methods are reserved for special use cases such as operator overloading or internal function definitions. Essentially, double underscores express certain core functionalities of the language, making it easier to understand and define Python code.

How Double Underscore Affects Method Name Mangling

One of the most significant ways that Python’s double underscore feature affects coding conventions is through method name mangling. Name mangling refers to the technique of prefixing a method name with a double underscore, which essentially changes the method’s name to an improperly formatted identifier. This technique helps protect the method from modification by external users, and serves as a way to explicitly denote that the method may be overridden in subclasses.

Comparing Single and Double Underscores

It’s important to note that while both single and double underscores denote particular functionalities in Python, there are critical differences between the two. Single underscores indicate that the class name or method is intended for internal use only, while double underscores act as a form of name mangling, allowing for further class privacy and inheritance control.

Single Underscore Double Underscore
Denotes private element Used in name mangling
Indicates convention, not enforced Mandatory in certain situations

The Benefits and Drawbacks of Double Underscores

The use of Python’s double underscores is a subject of much debate within the programming community. Some believe that utilizing this feature can help streamline code by making it more concise and easier to read, while others argue that overuse of double underscores can lead to unnecessary name-mangling and confusion.


  • Enhances code readability through explicit functionality definition
  • Assists in class privacy and inheritance control
  • Indicates reserved function use for built-in methods and objects


  • Overuse can lead to confusion and excessive name mangling
  • May be unnecessary in certain situations, leading to extraneous or bloated code
  • Can be difficult for beginners to understand and utilize correctly

How to Use Double Underscores Correctly

As with any coding convention or feature, it’s important to use double underscores judiciously and only when necessary. Ultimately, understanding the specific use cases for double underscores and taking care not to overuse them will help ensure cleaner, more readable, and more efficient Python code.

Comparing Double Underscores in Other Programming Languages

While Python’s use of double underscore is relatively unique, other programming languages have their own conventions and syntaxes for indicating reserved features and functionalities. For example, C# utilizes a double slash to denote comments, while Java relies on method modifiers such as public and private to signify visibility and access.

Programming Language Reserved Syntax
C# // comment
Java public void method() {}


Python’s double underscore feature is a unique and powerful tool that can help streamline coding conventions, enhance code readability, and provide greater control over class privacy and inheritance. However, it’s important to use this feature judiciously and only when necessary, to avoid unnecessary name mangling and confusion. By understanding the proper use cases for double underscores, Python developers can make the most of this critical tool and create more effective, efficient, and cleaner code.

Thank you for spending your time reading the Python’s Double Underscore Mystery: The What and Why [Duplicate] article. We hope that it has given you a deeper understanding of the concept of double underscores in Python, particularly their significance in object-oriented programming. We also hope that the article has clarified some of the confusion around their usage.

As you have learned, double underscores are used to indicate special methods or functions in Python. These special methods affect how an object behaves when certain operations are performed on them, such as addition or comparison. By using these special methods, developers have more control over how their objects behave and interact with other objects in their programs.

We encourage you to continue learning more about Python and its various features and functionalities, including the double underscore mystery. There are numerous resources available online for Python learners of all levels, and there are even Python communities where you can get support and connect with like-minded individuals. We wish you all the best in your Python learning journey!

Here are some common questions that people also ask about Python’s Double Underscore Mystery: The What and Why:

  1. What is the double underscore in Python?

    The double underscore, also known as the dunder or __ in Python, is used to define special methods or attributes. These methods and attributes have a specific meaning in Python and can be used to customize the behavior of your classes and objects.

  2. Why do we use double underscore in Python?

    Double underscore in Python is used to indicate special methods or attributes. These methods and attributes are used to customize the behavior of your classes and objects. For example, the __init__ method is called when an object is created and allows you to set initial values for the object’s attributes.

  3. What is name mangling in Python?

    Name mangling is a technique used by Python to avoid naming conflicts. When you use double underscores in a variable or method name, Python automatically adds the class name to the beginning of the name. This makes it less likely that two different classes will accidentally use the same name.

  4. What is the difference between single and double underscores in Python?

    Single underscores are typically used to indicate that a variable or method is intended to be private or protected. Double underscores, on the other hand, are used to define special methods or attributes that have a specific meaning in Python.

  5. What are some examples of special methods defined using double underscores?

    Some examples of special methods defined using double underscores include:

    • __init__: Defines the constructor method for a class.
    • __str__: Defines the string representation of an object.
    • __add__: Defines the behavior of the + operator for an object.
    • __len__: Defines the behavior of the len() function for an object.