Python Interview Questions & Answers for Freshers (2026)

Python is an interpreted, dynamically-typed, high-level language. It is known for readable syntax, automatic memory management (garbage collection), a huge standard library, support for multiple paradigms (procedural, OOP, functional), and being cross-platform. Its large ecosystem (NumPy, pandas, Django, PyTorch) makes it popular for AI, data and web.

A list is mutable (you can add, remove or change items) and uses square brackets [], while a tuple is immutable (cannot be changed after creation) and uses parentheses (). Tuples are slightly faster and can be used as dictionary keys; lists are used when the collection needs to change.

"==" compares values (are the two objects equal?), while "is" compares identity (are they the same object in memory?). For example two lists with the same contents are == but not "is". Use "is" mainly for checking against None.

Immutable types cannot change after creation: int, float, str, tuple, bool, frozenset. Mutable types can change in place: list, dict, set. This matters for function arguments — passing a mutable object lets the function modify the caller’s data.

A dict is a hash-map of key→value pairs with average O(1) lookup, insertion and deletion. Use it when you need fast lookups by a unique key, such as counting items, caching, or representing records. Keys must be hashable (immutable).

A concise way to build a list from an iterable: [x*x for x in range(5)] gives [0,1,4,9,16]. You can add a condition: [x for x in nums if x % 2 == 0]. It is more readable and usually faster than an equivalent for-loop with append.

A shallow copy (copy.copy) copies the outer object but shares references to nested objects, so changing a nested item affects both. A deep copy (copy.deepcopy) recursively copies everything, so the copy is fully independent.

*args lets a function accept any number of positional arguments as a tuple; **kwargs accepts any number of keyword arguments as a dict. They are used to write flexible functions and to forward arguments to other functions.

A decorator is a function that takes another function and returns a modified version, used to add behaviour (logging, timing, auth) without changing the original code. It is applied with the @decorator syntax above a function definition.

The GIL is a mutex in CPython that allows only one thread to execute Python bytecode at a time. It simplifies memory management but means CPU-bound multithreading does not speed up; use multiprocessing for CPU-bound work and threads/async for I/O-bound work.

Use try/except to catch exceptions, optionally with else (runs if no exception) and finally (always runs, for cleanup). Catch specific exceptions rather than a bare except, and raise to propagate or re-raise errors.

Python 3 is the current version: print is a function, division of ints gives a float, strings are Unicode by default, and many libraries are 3-only. Python 2 reached end-of-life in 2020 and should not be used for new work.