Question 1

How does iterable unpacking work?

Accepted Answer

**Target Audience:** Beginners to intermediate Python developers — you should know what a list and a tuple are.
**Difficulty:** Easy
**Python version:** Behaviour and `dis` output checked on CPython 3.11 (3.12 where noted); the examples also run in the page on Pyodide 0.25.1 (CPython 3.11.3).

> **How to read this doc:** Ideas come in plain language first. Words an interviewer expects you to use are tagged `📌 Interview term:` and defined on the spot, then listed again in the Quick Glossary. All

Question 2

What is the enum module and when should you use it?

Accepted Answer

**Target Audience:** Python beginners and intermediate developers who use strings or numbers as status codes and want to know what `enum` adds
**Difficulty:** Easy
**Python version:** Checked on CPython 3.11 (and in this page on Pyodide 0.25.1, which is CPython 3.11.3); differences in 3.12 are called out where we ran them

> **How to read this doc:** Each idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. Ever

Question 3

How are Python dictionaries implemented and ordered?

Accepted Answer

**Target Audience:** Beginners who use dicts daily and want to know what happens underneath; anyone preparing for a Python interview.
**Difficulty:** Easy
**Python version:** Behaviour checked on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime, which is CPython 3.11.3).

> **How to read this doc:** Each idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. Every output in the **Verified** section

Question 4

How do pyproject.toml, tomllib, and uv/pyproject workflows fit together?

Accepted Answer

**Target Audience:** Beginners who have run `pip install` but never set up a project from scratch; also experienced developers who want the precise names of each part.
**Difficulty:** Easy
**Python version:** The `tomllib` examples were run on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime, which is CPython 3.11.3). The uv commands were run with uv 0.11.32 against CPython 3.12.3.

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 I

Question 5

What do enumerate and zip do?

Accepted Answer

**Target Audience:** Beginners to intermediate Python developers preparing for interviews — you only need to know what a list and a `for` loop are.
**Difficulty:** Easy
**Python version:** Behaviour checked on CPython 3.11 (and 3.12 where noted); every example also runs in the page on Pyodide 0.25.1 (CPython 3.11.3).

> **How to read this doc:** Each idea is explained in plain language first. When a word appears that an interviewer expects you to know, it is tagged with `📌 Interview term:` and

Question 6

What is duck typing in Python?

Accepted Answer

**Target Audience:** Beginners who know functions and classes, and anyone who wants a crisp interview definition with real examples.
**Difficulty:** Easy
**Python version:** Behaviour checked on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime, which is CPython 3.11.3).

> **How to read this doc:** Each idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. Every output in the **Verified** section w

Question 7

What is the walrus operator?

Accepted Answer

**Target Audience:** Beginners who have seen `:=` and want to know when it helps; candidates who want the scope and syntax rules.
**Difficulty:** Easy
**Python version:** Available since Python 3.8. Behaviour checked on CPython 3.11.17 (and 3.13.16, same output) and in the page runner (Pyodide 0.25.1, CPython 3.11.3).

> **How to read this doc:** Every idea is explained in plain words, then tagged `📌 Interview term:` with the name an interviewer expects. All output is from real runs, collected

Question 8

How does exception handling work in Python?

Accepted Answer

**Target Audience:** Beginners learning Python, and anyone preparing for a Python interview
**Difficulty:** Easy
**Python version:** Every example was run on CPython 3.11 (and in this page on Pyodide 0.25.1, which is CPython 3.11.3)

> **How to read this doc:** Each idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. Every output block in the **Verified** section was copied from a real run of the examples on th

Question 9

What is structural pattern matching (match/case)?

Accepted Answer

**Target Audience:** Python developers who know `if`/`elif`, lists, dicts and classes and have never used `match`, plus anyone who wants the exact rules an interviewer probes.
**Difficulty:** Medium
**Python version:** `match` needs Python 3.10+. Behaviour and bytecode checked on CPython 3.11 (gotchas re-run on 3.13); both examples also run in the page on Pyodide 0.25.1 (CPython 3.11.3).

> **How to read this doc:** Ideas come in plain language first. The words an interviewer expects you to use

Question 10

What are abstract base classes and Protocols?

Accepted Answer

**Target Audience:** Developers who know classes and inheritance and have seen `ABC` or `Protocol` in a codebase, up to candidates who need to compare nominal and structural typing precisely.
**Difficulty:** Medium
**Python version:** Behaviour checked on CPython 3.11 (python3.11 and the in-page Pyodide 0.25.1 runtime, which is CPython 3.11.3); the differences we saw on 3.12 and 3.13 are called out.

> **How to read this doc:** Each idea is explained in plain language first, then tagged with `📌

PYTHONDECODED.

Easy

How does iterable unpacking work?

What is the enum module and when should you use it?

How are Python dictionaries implemented and ordered?

How do pyproject.toml, tomllib, and uv/pyproject workflows fit together?

What do enumerate and zip do?

What is duck typing in Python?

What is the walrus operator?

How does exception handling work in Python?

Medium

What is structural pattern matching (match/case)?

What are abstract base classes and Protocols?

What is the LEGB rule for scope resolution?

How does exception propagation work up the call stack?

How do you write tests in Python with unittest and pytest?

How do you raise and split ExceptionGroups manually?

How do default, keyword-only and positional-only parameters work?

How do you enforce match/case exhaustiveness in Python?

Hard

How does typing.Never enable exhaustive match checking?

What is TypeVarTuple and Unpack for variadic generics?