Python Interview Questions

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What is python Programming?

Python Programming is a high-level, interpreted programming language known for its simplicity, readability, and wide range of applications. Python supports object-oriented, procedural, and functional programming paradigms. It's commonly used in web development, data science, machine learning, automation, scripting, and more.

Here are 20 important Python interview questions that cover a range of topics:

1. What is Python?

Answer: Python is an interpreted, high-level, general-purpose programming language known for its simplicity and readability. It emphasizes code readability with its use of significant indentation.

2. What are Python’s key features?

Answer:
- Simple and easy to learn.
- High-level language.
- Interpreted and dynamically typed.
- Extensive standard libraries.
- Supports multiple programming paradigms (object-oriented, procedural, functional).

3. What is PEP 8 and why is it important?

Answer: PEP 8 is Python’s style guide for writing code. It promotes code readability and best practices, ensuring consistency across Python projects.

4. What are Python’s data types?

Answer: Python’s built-in data types include:
- Numeric types: int, float, complex
- Sequence types: list, tuple, range
- Text type: str
- Mapping type: dict
- Set types: set, frozenset
- Boolean type: bool
- Binary types: bytes, bytearray, memoryview

5. What is the difference between a list and a tuple?

Answer:
- List: Mutable (can be changed), defined using square brackets [].
- Tuple: Immutable (cannot be changed), defined using parentheses ().

6. What are functions in Python? How do you define a function?

Answer: Functions are blocks of reusable code that perform a specific task. They are defined using the def keyword:
```
python Code
def function_name(parameters):
    # function body
    return result
```

7. What is the difference between Python 2 and Python 3?

Answer: Python 3 introduced several improvements over Python 2, including:
- Print function as print()
- Integer division returning float (/)
- Unicode by default for strings
- Improved syntax and library support

8. **Explain the concept of *args and kwargs.

Answer:
- *args: Allows passing a variable number of non-keyword arguments.
- **kwargs: Allows passing a variable number of keyword arguments.

9. What is list comprehension in Python?

Answer: List comprehension is a concise way to create lists in Python. It allows for filtering and transforming elements in a single line:
```
python Code
squares = [x**2 for x in range(10)]
```

10. What is a lambda function in Python?

Answer: A lambda function is an anonymous function defined using the lambda keyword. It can have any number of arguments but only one expression:
```
python Code
add = lambda x, y: x + y
```

11. How does Python handle memory management?

Answer: Python uses an automatic garbage collection mechanism to manage memory. It includes:
- Reference counting.
- A cycle-detecting garbage collector for collecting cyclic references.

12. What are decorators in Python?

Answer: Decorators are functions that modify the behavior of other functions or methods. They are typically used to add functionality to an existing function in a clean and readable way.

13. What is the difference between deep copy and shallow copy?

Answer:
- Shallow copy: Creates a new object but inserts references to the original objects.
- Deep copy: Creates a new object and recursively copies all objects within it.

14. What is a Python module and package?

Answer:
- Module: A file containing Python code (functions, classes, variables) that can be imported.
- Package: A directory containing multiple modules, typically with an __init__.py file.

15. What is the Global Interpreter Lock (GIL) in Python?

Answer: The GIL is a mutex that protects access to Python objects, preventing multiple native threads from executing Python bytecodes simultaneously in a multi-threaded environment.

16. How can you handle exceptions in Python?

Answer: Python handles exceptions using the try-except block:

python Code
try:
    # code that may raise an exception
except Exception as e:
    # code to handle the exception

17. What is the difference between `is` and `==` in Python?

Answer:
- is: Checks for object identity (whether two references point to the same object in memory).
- ==: Checks for value equality (whether the values of two objects are the same).

18. What are generators in Python?

Answer: Generators are functions that return an iterable set of items, one at a time, using the yield keyword. They are more memory efficient than returning a full list.

19. Explain the difference between a class and an object in Python.

Answer:
- Class: A blueprint for creating objects. It defines properties and behaviors.
- Object: An instance of a class.

20. What is a docstring in Python?

Answer: A docstring is a string literal used to document a module, function, class, or method. It’s the first statement in the definition, and it's accessible through the __doc__ attribute.

These questions are often asked in Python interviews to gauge your knowledge of the language and its core concept.

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