pythonintermediate

Python Intermediate Quiz

List comprehensions, decorators, generators, exception handling, and OOP in Python.

7 questions

By EZ4Code TeamLast updated: 2026-08-01

1. What is the output of this list comprehension?

nums = [1, 2, 3, 4]
result = [x * 2 for x in nums if x % 2 == 0]
print(result)

[2, 4, 6, 8]

[4, 8]

[2, 6]

[1, 3]

Explanation: The comprehension iterates over `nums`, keeps only even numbers (`x % 2 == 0` → 2 and 4), and doubles them. So `[2*2, 4*2] = [4, 8]`.

2. What does a decorator do in Python?

Adds styling to a class

Modifies the behavior of a function without changing its code

Declares a static variable

Creates a new data type

Explanation: A decorator is a function that takes another function and extends its behavior without modifying the original function's source code. It uses the `@decorator_name` syntax above the function definition.

3. What is the result of this generator expression?

gen = (x ** 2 for x in range(3))
print(list(gen))

[0, 1, 2]

[0, 1, 4]

[1, 4, 9]

Explanation: `range(3)` yields 0, 1, 2. Squaring each gives 0, 1, 4. Wrapping with `list()` materializes the generator into a list. The generator itself prints as `<generator object>`, but `list(gen)` evaluates it.

4. Which exception is raised when dividing by zero?

result = 10 / 0

DivideByZeroError

ZeroDivisionError

ArithmeticError

ValueError

Explanation: Python raises `ZeroDivisionError` when you divide by zero. `ArithmeticError` is the parent class, but the specific subclass is `ZeroDivisionError`. There is no `DivideByZeroError` in Python (that's a C# name).

5. What does `self` refer to in a Python class method?

class Dog:
    def __init__(self, name):
        self.name = name

The class itself

The current instance of the class

The parent class

A static reference

Explanation: `self` refers to the current instance — it's the equivalent of `this` in Java/JavaScript. It's explicitly passed as the first parameter of instance methods. To reference the class itself, use `cls` (in classmethods) or the class name.

6. What is the output?

d = {"a": 1, "b": 2}
d.setdefault("c", 3)
d.setdefault("a", 99)
print(d)

{'a': 99, 'b': 2, 'c': 3}

{'a': 1, 'b': 2, 'c': 3}

{'a': 1, 'b': 2}

{'a': 99, 'b': 2}

Explanation: `setdefault(key, default)` only sets the value if the key is missing. `c` is missing, so it's set to 3. `a` already exists with value 1, so the call `setdefault('a', 99)` is a no-op — the value stays 1.

7. Which statement about `*args` and `**kwargs` is correct?

*args is a list, **kwargs is a list

*args is a tuple, **kwargs is a dict

*args is a dict, **kwargs is a tuple

Both are tuples

Explanation: Inside a function, `*args` collects positional arguments into a `tuple`, and `**kwargs` collects keyword arguments into a `dict`. The names `args` and `kwargs` are convention — only the `*` and `**` matter syntactically.