Question 1

What is the difference between a module and a package?

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 2

What does if __name__ == "__main__" do?

Accepted Answer

**Target Audience:** Beginners writing their first scripts and modules; anyone who has copied the line without knowing why.
**Difficulty:** Easy
**Python version:** Checked on CPython 3.11.17, 3.12.3 and 3.13.16 (identical output) and in the page runner (Pyodide 0.25.1, CPython 3.11.3).

> **How to read this doc:** Ideas come in plain words first, then a `📌 Interview term:` callout with the precise name an interviewer uses. Every output below is copied from a real run; the **Verified** section

Question 3

What is the difference between shallow and deep copy?

Accepted Answer

**Target Audience:** Beginners who have been surprised by "I changed the copy and the original changed too", and anyone preparing for the classic interview follow-ups on `copy`.
**Difficulty:** Medium
**Python version:** Behaviour checked on CPython 3.11 and 3.13, and in the page runner (Pyodide 0.25.1, CPython 3.11.3). `copy.replace()` needs 3.13.

> **How to read this doc:** Every idea is explained in plain language first, then tagged with `📌 Interview term:` so you also learn the exact words

Question 4

What is the LEGB rule for scope resolution?

Accepted Answer

**Target Audience:** Python beginners and intermediate developers preparing for interviews — you only need to know what a function is.
**Difficulty:** Medium
**Python version:** Behaviour checked on CPython 3.11, 3.12 and 3.13; the examples run 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, then tagged with `📌 Interview term:` so you also learn the exact word an interviewer expects. Every output shown was produced by

Question 5

What is monkey patching in Python?

Accepted Answer

**Target Audience:** Developers who have seen `mock.patch` in tests or a "quick fix" that reassigns a library function, up to candidates who must explain scope, the import trap and the risks.
**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); spot checks on 3.12 and 3.13 are noted.

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

Question 6

How does the Python import system work?

Accepted Answer

**Target Audience:** Python developers who know how to import things and want to know how importing works, and candidates for senior Python interviews
**Difficulty:** Hard
**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); Example 2 also gave identical output on 3.13

> **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

Question 7

How does CPython execute your code?

Accepted Answer

**Target Audience:** Python developers who have written functions and loops and want to know what the interpreter does with them. No C or compiler background is assumed.
**Difficulty:** Hard
**Python version:** Behaviour and `dis` output checked on CPython 3.11, with the differences on 3.12 and 3.13 shown where they matter. Both examples also run in the page on Pyodide 0.25.1 (CPython 3.11.3).

> **How to read this doc:** Every idea is explained in plain words first. When a word appears that an

Question 8

What is the difference between __getattr__ and __getattribute__?

Accepted Answer

**Target Audience:** Intermediate Python developers who know classes and methods and have seen `__getattr__` in library code.
**Difficulty:** Hard
**Python version:** Behaviour checked on CPython 3.11 (outputs identical on 3.12 and 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. Terms an interviewer expects you to use are tagged `📌 Interview term:` and defined where they appear; the Quick Glossary rep

PYTHONDECODED.

Easy

What is the difference between a module and a package?

What does if name == "main" do?

Medium

What is the difference between shallow and deep copy?

What is the LEGB rule for scope resolution?

What is monkey patching in Python?

Hard

How does the Python import system work?

How does CPython execute your code?

What is the difference between getattr and getattribute?