Question 1

What is the difference between a local variable and an instance variable in Ruby?

Accepted Answer

A local variable starts with a lowercase letter or underscore and is only accessible within its scope (method or block). An instance variable starts with @ and is accessible in all methods of the object, persisting throughout the instance's lifetime. This distinction is fundamental for state management in Ruby objects.

Question 2

How to declare a constant in Ruby and what is its naming convention?

Accepted Answer

In Ruby, a constant is declared using a name starting with an uppercase letter. By convention, constants are written in SCREAMING_SNAKE_CASE (e.g., MAX_SIZE = 100). Ruby emits a warning if a constant is modified, but doesn't prevent it unlike other languages.

Question 3

What is the result of the expression 5 / 2 in Ruby and how to get a decimal result?

Accepted Answer

In Ruby, division between two integers (Integer) returns an integer (5 / 2 = 2). To get a decimal result, at least one operand must be a Float: 5.0 / 2 or 5 / 2.0 or 5.to_f / 2. This rule follows the integer division principle present in many languages.

Ruby Basics

What is the difference between a local variable and an instance variable in Ruby?

Câu trả lời

How to declare a constant in Ruby and what is its naming convention?

Câu trả lời

What is the result of the expression 5 / 2 in Ruby and how to get a decimal result?

Câu trả lời

What is the difference between a Symbol (:name) and a String ("name") in Ruby?

How does string interpolation work in Ruby?

Các chủ đề phỏng vấn Ruby on Rails khác

Ruby Object-Oriented Programming

Rails Fundamentals

Routing & Controllers

ActiveRecord Basics

Views & ERB Templates

ActiveRecord Associations

Advanced ActiveRecord Queries

Rails Forms

Authentication & Authorization

Modern Asset Pipeline & Frontend

Rails API Mode

Testing with RSpec

ActiveJob & Background Jobs

ActionCable & WebSockets

ActionMailer

ActiveStorage

Caching Strategies

Advanced Migrations

Rails Engines & Modular Apps

Performance Optimization

Rails Design Patterns

Ruby Metaprogramming

Rails Security

GraphQL with Rails

Deployment & Production

Monitoring & Logging

Rails Upgrade Strategies

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