Python Interview Questions and Answers

Python is a high-level, interpreted programming language known for its readability and simplicity. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming.

Python's key features include:

• Readable and maintainable code
• Dynamic typing
• Interpreted language
• Extensive standard libraries
• Supports multiple programming paradigms
• Cross-platform compatibility

Python's built-in data types include:

• int: Integer type
• float: Floating-point type
• complex: Complex number type
• str: String type
• list: List type
• tuple: Tuple type
• dict: Dictionary type
• set: Set type

A Python function is a block of reusable code that performs a specific task. Functions are defined using the def keyword and can take arguments and return values.

Modules are Python files that consist of Python code. Packages are collections of modules grouped together in a directory hierarchy. Modules and packages help in organizing code and reusing functionality.

A list comprehension is a concise way to create lists in Python. It involves using a single line of code to generate a list based on some iterable, typically with a for loop and optional conditionals.

Python uses automatic memory management through a built-in garbage collector that handles memory allocation and deallocation. It uses reference counting and cyclic garbage collection to manage memory.

Exception handling in Python is done using the try and except blocks. It allows the program to handle runtime errors gracefully without crashing.

A shallow copy creates a new object but inserts references into it to the objects found in the original. A deepcopy creates a new object and recursively copies all objects found in the original, resulting in a completely independent object.

Decorators are functions that modify the behavior of another function or method. They are applied using the @decorator_name syntax above the function definition.

== checks for equality of values, while is checks for identity, meaning whether two variables point to the same object in memory.

A lambda function is an anonymous function defined with the lambda keyword. It is used for creating small, one-off functions without a name.

Lists are mutable, meaning their contents can be changed, while tuples are immutable and cannot be changed after creation. Tuples are often used for fixed collections of items.

Iterators are objects that implement the __iter__() and __next__() methods to iterate over a sequence. Generators are a type of iterator created using functions with the yield keyword, allowing for lazy evaluation.

Python supports multiple inheritance, allowing a class to inherit from multiple base classes. Python uses the C3 linearization algorithm to handle method resolution order (MRO) in cases of multiple inheritance.

Context managers are used to manage resources efficiently using the with statement. They define the methods __enter__() and __exit__() to handle setup and cleanup actions.

The self keyword is used in instance methods within a class to refer to the instance calling the method. It allows access to the instance's attributes and methods.

The GIL is a mutex that protects access to Python objects, preventing multiple threads from executing Python bytecodes simultaneously. This can impact multi-threaded Python programs, especially those involving CPU-bound tasks.

Python's built-in functions include print(), len(), type(), max(), min(), range(), sum(), among others. They provide common functionalities without needing to import additional modules.

List slicing is a technique to access a portion of a list using the start:stop:step syntax. It allows you to extract sublists or modify parts of a list.

A function is a block of reusable code that is not bound to any object, while a method is a function that is associated with an object and is called on that object.

The __init__ method is a special method used for initializing new instances of a class. It is called when an object is created and allows for setting initial values for the object's attributes.

You can handle missing keys using the get() method, which returns a default value if the key is not found. Alternatively, you can use the defaultdict class from the collections module for a dictionary with default values.

Decorators are functions that modify the behavior of another function or method. They are applied using the @decorator_name syntax and are useful for adding functionality to functions or methods without changing their code.

The __str__ method is used to define a human-readable string representation of an object. It is called by the str() function and the print() function to provide a user-friendly display of the object.

Python's primary data structures include lists, tuples, dictionaries, and sets. Each structure serves different purposes and provides various methods for data manipulation and retrieval.

File I/O in Python is performed using the built-in open() function. You can open files in different modes, such as read ('r'), write ('w'), and append ('a'). Use file.read(), file.write(), and file.close() for reading, writing, and closing files respectively.