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Top 25 Python Interview Questions and Answers (2026)

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Python is the most-assessed language on AI proctored assessment platforms and remains the default screen for data, backend and automation roles. Recruiters increasingly filter candidates through structured Python assessments before any human interview, so the questions below are the ones that reliably appear in those screens — grouped from basics to scenarios you should rehearse.

Why Python Interview Questions Still Gate Technical Hiring

Basic Python Interview Questions

What are Python's key features?

Python is dynamically typed, interpreted and garbage-collected, with first-class functions and strong support for modules and packages. Interviewers expect you to mention readability, an enormous standard library, and its two dominant versions (Python 3.x only in practice).

What is the difference between a list and a tuple?

Lists are mutable and tuples are immutable. Tuples can serve as dictionary keys and are slightly faster; lists are the default choice when contents change at runtime.

How is memory managed in Python?

Python uses reference counting as the primary mechanism, plus a cyclic garbage collector that finds reference cycles. Objects live in private heaps managed by the interpreter; you rarely touch memory directly.

What is PEP 8 and why does it matter?

PEP 8 is the official style guide for Python code. It matters because hiring teams read your code — consistent naming, spacing and imports make code review and proctored coding rounds easier to score.

What is the difference between == and is?

== compares values; is compares identity (same object in memory). A classic trap: small integers are interned, so 5 is 5 is True, but 1000 is 1000 is False in some contexts.

What are mutable default arguments and why are they a bug?

Default arguments are evaluated once at function definition. A mutable default like def append_to(item, bucket=[]) shares one list across all calls. The idiomatic fix is a None default and an explicit new list inside the function.

Intermediate Questions

What are decorators and when would you write one?

A decorator is a callable that wraps another function to add behaviour — timing, caching, auth or retries — without changing its code. Write functools.wraps inside your decorator to preserve metadata; interviewers look for that detail.

Explain list comprehensions and generator expressions.

List comprehensions build the whole list in memory: [n n for n in range(10)]. Generator expressions are lazy: (n n for n in range(10)) produces values on demand, which matters for large datasets and pipelines.

What is the difference between shallow and deep copy?

A shallow copy copies the outer container but shares inner objects; a deep copy recursively duplicates everything, so mutating nested data in one copy never leaks into the other.

How does a Python dictionary work internally?

Dicts are hash maps: keys are hashed into slots with open addressing for collisions. That is why keys must be hashable (immutable) and lookups are O(1) on average.

What is the Global Interpreter Lock (GIL)?

The GIL lets only one thread execute Python bytecode at a time in CPython. Threads help with I/O-bound work, but CPU-bound concurrency needs multiprocessing or native extensions that release the GIL during execution.

How do context managers work?

Context managers implement __enter__ and __exit__ (or wrap a generator with contextlib), guaranteeing setup/teardown around a block. The canonical example is closing a file even when an exception is raised.

What is *args and **kwargs?

They collect arbitrary positional and keyword arguments into a tuple and a dict respectively. Combine them to write forward-compatible wrappers and APIs.

How does Python resolve method resolution order (MRO)?

Python 3 uses C3 linearisation: a class lookup order preserves inheritance graph order and local precedence. Explain it with the diamond problem — class D(B, C) where B and C both inherit from A.

Advanced and Scenario Questions

How would you profile and speed up a slow Python function?

Start with cProfile to find hotspots, then micro-benchmark with timeit. Typical wins: move work out of loops, use built-ins (which are C-accelerated), cache results with functools.lru_cache, and vectorise numeric work with libraries instead of pure Python loops.

How do you handle exceptions properly in a large codebase?

Catch the narrowest exception you can act on, log context, and never swallow errors silently. Use custom exception classes for domain errors and let truly unexpected failures propagate.

Explain race conditions in multithreaded Python code.

Two threads reading-modifying-writing shared state can interleave mid-update, producing lost updates. Protect shared state with locks, prefer queues for producer/consumer patterns, or move to multiprocessing for CPU-bound parallelism.

When would you choose dataclasses over plain classes?

Dataclasses generate __init__, __repr__ and __eq__ from annotated fields, cutting boilerplate. Choose them for value objects and records; reach for full classes when behaviour dominates.

How would you design a rate limiter in Python?

A token bucket or sliding-window counter over user IDs: tokens refill at a fixed rate and requests consume tokens. Discuss in-memory vs Redis-backed implementations and the trade-off under horizontal scaling.

Practice With the Real Assessment Format

Most interviewers pull from this same pool — but written, proctored rounds time-box every question. Rehearse against the real format: TalentIQ's Python assessment runs technical MCQs, short answers and a timed coding round under live AI proctoring, then scores you against candidates nationwide.

Start a free Python assessment on TalentIQ

Frequently Asked Questions

How many Python interview questions should I prepare?

Master the 25 above plus your project's specific libraries. Depth on 25 questions beats shallow exposure to 200 — interviewers probe for reasoning, not memorised syntax.

Are Python interview questions the same for freshers and experienced candidates?

They overlap, but expectation differs. Freshers get basics and small coding exercises; experienced candidates face architecture, performance and concurrency scenarios like the rate limiter above.

What Python versions should I know for interviews?

Know Python 3.10+ syntax: match statements, newer typing features and f-string debugging. Versions below 3.8 appear only in legacy codebases.

How do I practice Python coding under interview conditions?

Use a timed, proctored environment rather than open-ended practice. TalentIQ's free assessments simulate the exact format — MCQ round, coding test with real test cases and an AI interview — and give you a percentile score report.

Frequently Asked Questions

How many Python interview questions should I prepare?

Master the 25 above plus your project's specific libraries. Depth on 25 questions beats shallow exposure to 200 — interviewers probe for reasoning, not memorised syntax.

Are Python interview questions the same for freshers and experienced candidates?

They overlap, but expectation differs. Freshers get basics and small coding exercises; experienced candidates face architecture, performance and concurrency scenarios like the rate limiter above.

What Python versions should I know for interviews?

Know Python 3.10+ syntax: match statements, newer typing features and f-string debugging. Versions below 3.8 appear only in legacy codebases.

How do I practice Python coding under interview conditions?

Use a timed, proctored environment rather than open-ended practice. TalentIQ's free assessments simulate the exact format — MCQ round, coding test with real test cases and an AI interview — and give you a percentile score report.

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