Top 15 Python Interview Questions for Freshers with Answers

Q1. What are Python's key features?

Interpreted (no compilation step), dynamically typed (no type declarations), object-oriented, huge standard library, and readable indentation-based syntax. Bonus: mention it is both scripting and general-purpose.

Q2. Difference between list and tuple?

List is mutable with [ ], tuple is immutable with ( ). Tuple is faster, uses less memory, and can be a dictionary key. Use tuple for fixed data like coordinates.

Q3. What is the difference between == and is?

== compares values, is compares identity (same object in memory). Use is only for None checks: if x is None.

Q4. What are mutable and immutable types?

Mutable: list, dict, set — change in place. Immutable: int, str, tuple — any change creates a new object. Prove it with id() before and after.

Q5. What is indentation in Python?

Python uses indentation (spaces) instead of { } to define code blocks. Standard is 4 spaces; inconsistent indentation raises IndentationError.

Q6. What is a lambda function?

An anonymous one-line function: lambda x: x*x. One expression only, auto-returned. Best inside sorted(key=...), map() and filter().

Q7. What is self?

The reference to the current object. Python automatically passes the object before the dot as the first argument, and self receives it. It is a convention, not a keyword.

Q8. What is __init__?

The constructor method, called automatically when an object is created. It initializes the object's attributes: def __init__(self, name): self.name = name.

Q9. Difference between append() and extend()?

append adds its argument as one item (+1 length); extend adds each element of an iterable individually (+N length). a.append([4,5]) nests; a.extend([4,5]) doesn't.

Q10. What are *args and **kwargs?

*args collects extra positional arguments into a tuple; **kwargs collects extra keyword arguments into a dict. They let a function accept any number of arguments.

Q11. Predict: print(3 * "ab")

Output: ababab — string repetition. Similarly [0] * 3 gives [0, 0, 0].

Q12. Predict: print(10 / 3, 10 // 3, 10 % 3)

Output: 3.3333333333333335 3 1 — / always returns float, // is floor division, % is remainder.

Q13. Predict:

a = [1, 2, 3]
b = a
b.append(4)
print(a)

Output: [1, 2, 3, 4] — b = a copies the reference, not the list. Both names share one object. To copy: b = a.copy() or b = a[:].

Q14. What is the output of bool("False")?

True! Any non-empty string is truthy — even the string "False". Only empty containers, 0, and None are falsy.

Q15. Predict:

def f(x, lst=[]):
    lst.append(x)
    return lst
print(f(1)); print(f(2))

Output: [1] then [1, 2] — the mutable default list is created once and shared across calls. Fix: default None, create list inside.