How to Use Name Mangling in Python

In this article, we’re going to uncover a hidden gem of Python programming – the concept of “Name Mangling”. It may sound a bit like a fantasy novel, but it’s a practical and powerful feature that’s great to have in your coding toolkit. So, let’s dive right in!

What is Name Mangling?

“Name Mangling” is a unique Python trick involving a special use of the double underscore (__). When we use double underscores before a variable in a class, Python tweaks the variable’s name to make it harder to access unintentionally. This isn’t about creating secret variables, but rather, it’s about avoiding errors in larger programs with many moving parts.

Name Mangling in Action

Let’s see how it works with a simple example:

class MyCoolClass:
    def __init__(self):
        self.__secretVariable = 123

obj = MyCoolClass()
print(obj.__secretVariable)

When you run this, Python will throw an error: AttributeError: 'MyCoolClass' object has no attribute '__secretVariable'.

“But wait!” you might say. “I can see the __secretVariable right there in the class!” Well, that’s where Name Mangling comes into play. Python has subtly changed the name of __secretVariable, so it’s not directly accessible as it appears.

When you run this, Python will throw an error: AttributeError: 'MyCoolClass' object has no attribute '__secretVariable'.

“But wait!” you might say. “I can see the __secretVariable right there in the class!” Well, that’s where Name Mangling comes into play. Python has subtly changed the name of __secretVariable, so it’s not directly accessible as it appears.

Unlocking the Secret

To access the mangled variable, you’d use _classname__variableName. Let’s try that:

print(obj._MyCoolClass__secretVariable)

And voila! The console now prints 123. Our hidden variable has been successfully revealed.

Wrapping Up

Name Mangling is a quirky but handy feature of Python. It’s all about creating a safe space for your variables, preventing unexpected clashes in big programs.

Remember, Python’s philosophy is “We’re all consenting adults here.” Name Mangling doesn’t make a variable private or hidden. It’s just a gentle reminder saying, “Hey, be careful when you’re accessing this!”.

Happy Pythoning and see you in the next post!