Python Interview Questions. Part II. Middle

#python #programming #interview

included. Some of the questions might even feel a little odd or out there. But in my experience, they're great at helping you figure out who's really ready for the job.

The series is split into three parts based on experience level:

Got a question you think should be here? Or something you always ask in interviews? Let me know — I'd love to hear your thoughts!

Questions

1. Python Language Concepts

Q: What is the output of -12 % 10?

Q: What is the output of -12 // 10?

Q: What is the sequence of operators called in the expression a * b * c?

Q: Why shouldn't you use a mutable object (e.g., an empty list) as a default argument in Python?

Q: What does the id() function in Python do?

Q: What are Python's comprehensions (list, dict, set)? When should you use them?

Q: What is the yield keyword used for in Python?

Q: How do you differentiate between iterators and generators in Python?

Bonus: Write an example of each.

Q: What is the difference between __iter__ and __next__ methods?

Q: How can you create a dictionary that preserves the order of key-value pairs?

Q: What are try, except, else, and finally blocks? Provide examples.

2. Context Managers

Q: What is a context manager, and how does it differ from using try...finally?

Q: Which methods must be implemented to create a custom context manager class?

Q: Explain with blocks. Why are they considered more Pythonic than try-finally?

Q: Describe a use case where context managers can be helpful.

3. Async basics

Q: What is synchronous code, and how does it differ from asynchronous code?

Q: How do async functions differ from normal Python functions?

Q: What are async and await keywords in Python? Provide a simple example.

Follow-up: What does await do, and when should it be used?

Q: What is the purpose of an event loop in Python, and how does the asyncio.run() function interact with it?

Q: How do you handle exceptions in asynchronous Python code?

Q: Can you explain the purpose of async with and async for constructs? Provide examples.

Q: How can you perform file I/O asynchronously in Python?

Q: When would you choose async programming over multi-threading in Python?

4. Advanced Concepts

Q: What is unittest module in Python? How to write tests in Python?

Q: Explain type checking in Python. Why is Python considered a strongly-typed language?

Q: How do you isolate Python code effectively (e.g., virtual environments)?

Q: How can you copy an object in Python? What's the difference between a shallow copy and a deep copy?

Q: How is memory managed in Python?

Follow-up: Why does Python have a garbage collector, and how does it work?

Q: How can you share global variables across modules? Is it a good idea to do so?

Q: What is the __slots__ attribute in a class? What are its benefits and drawbacks?

Q: What are metaclasses in Python?

Bonus: How can you create a class without using the class statement?

5. Coding Challenges

Q: How to check that one tuple contains all elements of another tuple?

Q: What will be the output of the following code?

>>> list = ['a', 'b', 'c', 'd', 'e']
>>> print(list[10:]) # []

Q: How can I reload a previously imported module? (we assume that the module is a file module.py)

Q: What will be the output of the following code?

>>> a = [[]] * 3
>>> a[1].append(1)
>>> print(a)  # [[1], [1], [1]]

Q: What's wrong with the following code?

def foo():
    from .module import *
    print(f"{bar()}")

Q: The file is located in /usr/lib/python/person.py. The program is run with python /usr/lib/python/person.py. What will the output be?

class Person:
    def __init__(self, name):
        __name__ = name

    def getAge(self):
        print(__name__)

p = Person("John")
p.getAge()

Q: Write a timeit decorator to measure the time of function execution.

Q: Write a decorator that will catch errors and repeat the function a maximum of 3 times (configurable).

Q: What's the output of the following code?

class parent:
    def __init__(self, param):
        self.v1 = param

class child:
    def __init__(self, param):
        self.v2 = param

obj = child(11)
print(obj.v1 + " " + obj.v2)

Q: Fix the following code to make it work.

class Repeater:
    ...
class RepeaterIterator:
    ...

repeater = Repeater("Hello")
for i in repeater:
    print(i)  # hello

Q: Write code to get unique values from a list of complex types (custom classes). Example: [A(1, "ab"), A(2, "ab"), A(2, "aa"), A(1, "ab)] -> [A(1, "ab"), A(2, "ab"), A(2, "aa")].

Q: We have the following code with the unknown function f(). In f(), we do not want to use a return, instead, we may want to use a generator.

for x in f(5):
    print(x,)

The output looks like this:

0 1 8 27 64

Write a function f() so that we can have the output above.