Python · topic 1 of 1

Python

Data structures, comprehensions, decorators, the GIL.

Questions below are grouped from foundations to advanced. Work top to bottom if the topic is new to you, or jump to a level if you are brushing up.

Questions: 27
Difficulty mix: 16 easy · 10 medium · 1 hard

Topics covered

Data Types3
Lists2
Functions2
Lists & Dicts1
Decorators1
Tuples1
Dictionaries1
Sets1
Strings1
Lambda1
Comprehensions1
Exceptions1
File Handling1
OOP1
Modules1
Environments1
Generators1
Iterators1
Inheritance1
Polymorphism1
Encapsulation1
Concurrency1
GIL1

Foundations

Easy · 16 questions

Definitions and building blocks — start here if the topic is new to you.

What is the difference between a list and a tuple in Python?
Lists & DictsEasy
What is the difference between mutable and immutable types in Python?
Data TypesEasy
What is the difference between `is` and `==` in Python?
Data TypesEasy
What is the difference between append() and extend() on a list?
ListsEasy
How does slicing work, and how do you reverse a string or list with it?
ListsEasy
When would you use a tuple, and what are packing, unpacking and namedtuple?
TuplesEasy
How do you safely read and update dictionary values (get, setdefault, Counter)?
DictionariesEasy
What is a set in Python and when should you use one?
SetsEasy
Are Python strings mutable, and how do you build/format them efficiently?
StringsEasy
What is a lambda function and when should you use one?
LambdaEasy
What is a list comprehension and why is it preferred over a loop?
ComprehensionsEasy
How does exception handling work in Python (try/except/else/finally)?
ExceptionsEasy
What is the right way to read and write files in Python?
File HandlingEasy
What are __init__ and self in a Python class?
OOPEasy
What are modules and packages, and how does import work?
ModulesEasy
What is a virtual environment and why does every Python project need one?
EnvironmentsEasy

Core concepts

Medium · 10 questions

The questions most interviews spend their time on: how it works and when to use it.

What is a decorator in Python?
DecoratorsMedium
What is the difference between a shallow copy and a deep copy?
Data TypesMedium
Why is a mutable default argument (like def f(x, items=[])) dangerous?
FunctionsMedium
What are *args and **kwargs, and how do you use them?
FunctionsMedium
What is a generator and how does yield work?
GeneratorsMedium
What is the difference between an iterable and an iterator?
IteratorsMedium
How does inheritance work in Python, and what does super() do?
InheritanceMedium
What is polymorphism and duck typing in Python?
PolymorphismMedium
How does encapsulation work in Python (_ , __ , and @property)?
EncapsulationMedium
When should you use multithreading vs multiprocessing in Python?
ConcurrencyMedium

Advanced

Hard · 1 question

Internals, trade-offs and edge cases — useful for senior rounds and follow-ups.

What is the GIL (Global Interpreter Lock) and what are its implications?
GILHard

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Topics covered

Foundations

What is the difference between a list and a tuple in Python?

What is the difference between mutable and immutable types in Python?

What is the difference between `is` and `==` in Python?

What is the difference between append() and extend() on a list?

How does slicing work, and how do you reverse a string or list with it?

When would you use a tuple, and what are packing, unpacking and namedtuple?

How do you safely read and update dictionary values (get, setdefault, Counter)?

What is a set in Python and when should you use one?

Are Python strings mutable, and how do you build/format them efficiently?

What is a lambda function and when should you use one?

What is a list comprehension and why is it preferred over a loop?

How does exception handling work in Python (try/except/else/finally)?

What is the right way to read and write files in Python?

What are __init__ and self in a Python class?

What are modules and packages, and how does import work?

What is a virtual environment and why does every Python project need one?

Core concepts

What is a decorator in Python?

What is the difference between a shallow copy and a deep copy?

Why is a mutable default argument (like def f(x, items=[])) dangerous?

What are *args and **kwargs, and how do you use them?

What is a generator and how does yield work?

What is the difference between an iterable and an iterator?

How does inheritance work in Python, and what does super() do?

What is polymorphism and duck typing in Python?

How does encapsulation work in Python (_ , __ , and @property)?

When should you use multithreading vs multiprocessing in Python?

Advanced

What is the GIL (Global Interpreter Lock) and what are its implications?

What are init and self in a Python class?