10+ Interview Questions and Answers

Memory management in Python involves automatic memory allocation and deallocation through garbage collection.

• Python uses automatic memory management through garbage collection, so manual memory management is not required.

• Use tools like memory_profiler to identify memory leaks and optimize memory usage.

• Avoid creating unnecessary objects and use data structures efficiently to minimize memory usage.

select_related follows foreign key relationships and retrieves related objects in a single query, while prefetch_related retrieves related objects separately to avoid performance issues.

• select_related is used for accessing related objects in a single query, reducing database hits

• prefetch_related is used for accessing related objects separately to avoid performance issues

• select_related is more efficient for one-to-one or many-to-one relationships, while prefetch_related is bet...read more

Tuple is an ordered collection of elements. Closures are self-contained blocks of code. Delegates are references to functions. Notifications are a way to send messages between objects.

• Tuple: Used to group multiple values together. Example: (1, 'apple', True)

• Closures: Encapsulate code and capture variables. Example: { (x: Int) -> Int in return x * 2 }

• Delegates: Allow one object to communicate with another. Example: UITableViewDelegate

• Notifications: Broadcast messages to multip...read more

React is a JavaScript library for building user interfaces, while Angular is a full-fledged framework for building web applications.

• React is a library, while Angular is a framework

• React uses a virtual DOM, while Angular uses a real DOM

• React is more lightweight and flexible, while Angular has more built-in features and tools

• React is easier to learn for beginners, while Angular has a steeper learning curve

• React is maintained by Facebook, while Angular is maintained by Google

Async is non-blocking, Sync is blocking, Multithread allows multiple threads to run concurrently.

• Async allows the program to continue executing other tasks while waiting for a response, commonly used in web development with AJAX calls.

• Sync blocks the program until a task is completed, commonly used in simple sequential programs.

• Multithreading allows multiple threads to run concurrently, improving performance by utilizing multiple CPU cores, commonly used in applications with ...read more

Decorator is a design pattern in software development that allows behavior to be added to individual objects, either statically or dynamically.

• Decorators are used to modify the behavior of functions or classes without changing their source code.

• In Python, decorators are implemented using the @ symbol followed by the decorator function name.

• Example: @decorator_function def some_function(): # function implementation

• Decorators can be used for logging, authentication, caching, et...read more

Single design patterns work by providing a reusable solution to common problems in software development.

• Design patterns help in organizing code and making it more maintainable.

• They promote code reusability and flexibility.

• Examples of single design patterns include Singleton, Factory, and Observer.

MVVM is a software architectural pattern that separates the user interface from the business logic and data.

• MVVM stands for Model-View-ViewModel

• Model represents the data and business logic

• View represents the user interface

• ViewModel acts as a mediator between the Model and View

• ViewModel exposes data and commands to the View

• MVVM promotes separation of concerns and testability

• Example: Using MVVM in a mobile app, the ViewModel would handle data retrieval and manipulation, while t...read more

Use 'git revert' command to revert the last commit.

• Use 'git log' to find the commit hash of the last commit

• Run 'git revert ' to revert the last commit

• Commit the revert changes with a new commit message

Optimizing query involves indexing, minimizing data retrieval, using proper joins, and avoiding unnecessary functions.

• Use indexes on columns frequently used in WHERE clauses

• Minimize data retrieval by selecting only necessary columns

• Use proper joins (INNER JOIN, LEFT JOIN, etc.) instead of subqueries

• Avoid unnecessary functions in WHERE clauses

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization is used to eliminate redundant data and ensure data dependencies are logical.

• It involves dividing a database into two or more tables and defining relationships between them.

• Normalization helps in reducing data redundancy, improving data integrity, and making data maintenance easier.

• There are different normal forms such as 1NF, 2NF, 3NF, BCNF, and 4NF, ea...read more

To increase performance, optimize code, use efficient algorithms, parallel processing, caching, and database indexing.

• Optimize code by reducing unnecessary loops and improving data structures

• Use efficient algorithms like binary search instead of linear search

• Implement parallel processing to utilize multiple CPU cores

• Utilize caching to store frequently accessed data for faster retrieval

• Implement database indexing to speed up query performance