Navigators Software System Engineer Interview Questions and Answers

List is mutable and can be changed, while tuple is immutable and cannot be changed.

• List can be modified using methods like append, remove, and pop.

• Tuple elements cannot be changed once assigned.

• Lists are denoted by square brackets [], while tuples are denoted by parentheses ().

A decorator is a design pattern in object-oriented programming that allows behavior to be added to individual objects, either statically or dynamically, without affecting the behavior of other objects.

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

• They are often used for adding functionalities like logging, caching, or authentication to existing code.

• In Python, dec...read more

PHP OOP (Object-Oriented Programming) enhances code reusability and organization through classes and objects.

• Encapsulation: Bundling data and methods that operate on the data within one unit (class). Example: class User { private $name; }

• Inheritance: Mechanism to create a new class using properties and methods of an existing class. Example: class Admin extends User {}

• Polymorphism: Ability to redefine methods in derived...read more

List is mutable, tuple is immutable in Python.

• List can be modified after creation, tuple cannot be modified

• List is defined using square brackets [], tuple using parentheses ()

• List is used for collections of items that may change, tuple for fixed collections

Shallow copy creates a new object but does not duplicate nested objects, while deep copy creates a new object with all nested objects duplicated.

• Shallow copy only copies the references of nested objects, not the objects themselves.

• Deep copy creates new instances of all nested objects.

• Shallow copy is faster and more memory efficient, but changes to nested objects in the original object will reflect in the copied object.

• ...read more

Parameters are variables in a function definition, while arguments are the actual values passed to the function.

• Parameters are defined in the function signature, arguments are passed when calling the function.

• Parameters are placeholders for data, arguments are the actual data passed to the function.

• Parameters are used to initialize variables within a function, arguments are the values assigned to those variables.

• Exampl...read more

Parsing a csv file without pandas

• Open the csv file using the built-in open() function

• Read the file line by line using a for loop

• Split each line by the comma delimiter to get individual values

Left join includes all records from the left table and matching records from the right table, while right join includes all records from the right table and matching records from the left table.

• Left join keeps all records from the left table, even if there are no matches in the right table.

• Right join keeps all records from the right table, even if there are no matches in the left table.

• Example: Left join - SELECT * FRO...read more

ACID properties are a set of properties that guarantee database transactions are processed reliably.

• ACID stands for Atomicity, Consistency, Isolation, Durability

• Atomicity ensures that all operations in a transaction are completed successfully or none at all

• Consistency ensures that the database remains in a consistent state before and after the transaction

• Isolation ensures that transactions are independent of each other

• ...read more

Encapsulation is the concept of bundling data and methods that operate on the data, while data abstraction is the concept of hiding the implementation details and showing only the necessary details to the user.

• Encapsulation involves bundling data and methods together in a class, providing access control to protect data from outside interference.

• Data abstraction involves hiding the implementation details and showing onl...read more

Stateless server does not store any client session information, while stateful server stores client session information.

• Stateless server treats each request as an independent transaction.

• Stateful server maintains client session information between requests.

• Stateless servers are easier to scale horizontally.

• Stateful servers are more complex to scale due to session data.

• Examples: Stateless - RESTful APIs, Stateful - TCP ...read more

Put method is used to create or replace a resource, while patch method is used to update a resource partially.

• Put method is idempotent, meaning multiple identical requests will have the same effect as a single request.

• Patch method is not idempotent, as multiple identical requests may have different effects.

• Put method requires the client to send the entire updated resource, while patch method only requires the specific ...read more