25-Most common interview question

with answers on Python for freshers 

1. Differentiate between list and tuple:
Lists are mutable data structures in Python, allowing for dynamic changes, while tuples are immutable. This means that elements in a list can be added, removed, or modified, while elements in a tuple cannot be changed once assigned.

2. How is memory managed in Python?
Python employs automatic memory management and a garbage collector. Objects and their references are tracked, and when an object is no longer in use, the interpreter automatically reclaims the associated memory.

3. How does range work?
The `range` function generates a sequence of numbers within a specified range. It includes the start value, goes up to (but does not include) the stop value, and increments by the specified step value.

4. What are pickling and unpickling?
Pickling is the process of converting a Python object into a byte stream, and unpickling is the reverse process of reconstructing the original object from the byte stream. This is commonly used for object serialization and deserialization.

5. What is docstring in Python?
A docstring in Python is a string literal used for documenting modules, classes, functions, or methods. It provides information about the purpose, usage, and parameters of the code and is placed at the beginning of the object’s definition.

6. Define modules in Python:
Modules in Python are files containing Python code. They allow the organization of code into separate files, providing a way to create modular and reusable code structures.

7. Define PYTHONPATH:
PYTHONPATH is an environment variable in Python that specifies a list of directories where the interpreter should look for modules and packages. It aids in locating modules and packages not in the same directory as the script or interpreter.

8. Differentiate between NumPy and SciPy:
NumPy focuses on numerical operations, providing support for large, multi-dimensional arrays and matrices. SciPy, built on NumPy, extends functionality, including optimization, signal processing, and more.

9. How is Python interpreted?
Python is interpreted, meaning code is executed line by line by the interpreter. It translates the source code into intermediate bytecode, which is then executed by the Python Virtual Machine (PVM).

10. What are functions in Python?
Functions in Python are blocks of reusable code defined using the `def` keyword. They may take parameters and return a value, promoting code reusability and organization into modular units.

11. What are lambda functions?
Lambda functions, also known as anonymous functions, are concise, one-line functions defined using the `lambda` keyword in Python. They are often used for short, simple operations and can take multiple arguments but have only one expression.

12. What is `__init__`?
`__init__` is a special method in Python classes that is automatically called when an object is created. It initializes the object’s attributes and is commonly used to set up the initial state of an instance.

13. What is PEP 8?
PEP 8 is the Python Enhancement Proposal that provides style guide recommendations for writing readable and consistent Python code. It covers topics such as indentation, naming conventions, and code layout to enhance code quality.

14. What is slicing in Python?
Slicing in Python refers to extracting a portion of a sequence, like a list or a string, using the colon (`:`) operator. It allows you to specify a start index, stop index, and an optional step value to create a new sequence.

15. What is type conversion in Python?
Type conversion, also known as type casting, involves changing the data type of a variable from one type to another. Python provides functions like `int()`, `float()`, and `str()` for type conversion.

16. Differentiate Between Deep And Shallow Copies:
In Python, a shallow copy creates a new object but references the same objects as the original, while a deep copy creates a new object and recursively copies all objects referenced by the original, resulting in independent copies.

17. How is multithreading achieved in Python?
Multithreading in Python is achieved using the `threading` module. It allows the execution of multiple threads (smaller units of a process) concurrently, enabling parallelism and improved performance for certain types of tasks.

18. Java vs Python:
Java and Python are both powerful, high-level programming languages, but they differ in terms of syntax, execution speed, and use cases. Java is statically typed, compiled, and commonly used for enterprise applications, while Python is dynamically typed, interpreted, and known for its readability and versatility.

19. What are decorators?
Decorators in Python are functions that modify the behavior of other functions or methods. They are used to add functionality to existing code without modifying its structure, enhancing readability and maintainability.

20. What Are dict and list comprehensions?
Dictionary and list comprehensions are concise ways to create dictionaries and lists in Python. They use a compact syntax to generate these data structures in a single line, making the code more readable and expressive.

21. What are Python iterators?
Iterators in Python are objects that implement the `__iter__()` and `__next__()` methods, allowing them to be iterated over. They are used in `for` loops and enable efficient traversal of data structures.

22. What are Python namespaces?
Namespaces in Python are containers that hold names defined in a program. They help in avoiding naming conflicts by organizing names into different scopes, such as local, global, and built-in namespaces.

23. What is `pass` in Python?
`pass` is a null statement in Python that serves as a placeholder. It is used when a statement is syntactically required but no action is desired. It allows the code to pass over a block without executing any specific instructions.

24. What is `self` in Python?
In Python, `self` is a conventionally used name for the first parameter in a class method. It refers to the instance of the class and is used to access and modify the attributes and methods of the object.

25. Briefly explain types of Inheritance:
Inheritance in Python allows a class (subclass) to inherit attributes and methods from another class (superclass). There are different types of inheritance, including single inheritance (one superclass), multiple inheritance (multiple super classes), multilevel inheritance, and hierarchical inheritance.

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