Name mangling in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to access the mangled private variable inside the class.

Python

class MyClass:
    def __init__(self):
        self.__secret = 42

obj = MyClass()
print(obj.[1])

Drag options to blanks, or click blank then click option'

Asecret

B__secret

C_MyClass__secret

D_secret

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to access __secret directly causes an AttributeError.

Using _secret or secret does not match the mangled name.

In Python, variables with double underscores are name-mangled to include the class name. So __secret becomes _MyClass__secret.

2fill in blank

medium

Complete the code to define a method that accesses the mangled private variable.

Python

class SecretHolder:
    def __init__(self):
        self.__hidden = 'safe'
    def reveal(self):
        return self.[1]

Drag options to blanks, or click blank then click option'

A_SecretHolder__hidden

B__hidden

C_hidden

Dhidden

Attempts:

3 left

💡 Hint

Common Mistakes

Using __hidden directly inside the method.

Using _hidden or hidden which are not the mangled names.

The method must use the mangled name _SecretHolder__hidden to access the private variable.

3fill in blank

hard

Fix the error in accessing the private variable from outside the class.

Python

class Data:
    def __init__(self):
        self.__value = 100

obj = Data()
print(obj.[1])

Drag options to blanks, or click blank then click option'

A__value

B_Data__value

C_value

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to access __value directly causes AttributeError.

Using _value or value does not match the mangled name.

Outside the class, the private variable must be accessed using the mangled name _Data__value.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps attribute names to their mangled values.

Python

class Info:
    def __init__(self):
        self.__a = 1
        self.__b = 2

obj = Info()
attrs = {name: getattr(obj, [1]) for name in ['a', 'b'] if hasattr(obj, [2])}

Drag options to blanks, or click blank then click option'

A'_Info__' + name

B'__' + name

C'_' + name

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using '__' + name misses the class name prefix.

Using '_' + name or just name does not match mangled names.

The mangled names are formed by prefixing the class name and double underscore to the attribute name, like _Info__a.

5fill in blank

hard

Fill all three blanks to define a class with a private variable, a method to access it, and external access using name mangling.

Python

class Secret:
    def __init__(self, val):
        self.[1] = val
    def get_secret(self):
        return self.[2]

s = Secret('hidden')
print(s.[3])

Drag options to blanks, or click blank then click option'

A__data

B_Secret__data

D__secret

Attempts:

3 left

💡 Hint

Common Mistakes

Using __secret instead of __data.

Accessing the variable outside the class without mangling.

The private variable is named __data. Inside the class, it is accessed as _Secret__data due to name mangling. Outside, the mangled name _Secret__data is used to access it.