Most Frequently Asked Ruby Interview Questions

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Ruby is an open-source, dynamic, and general-purpose programming language focused on simplicity and productivity. It has an easy syntax.

Whether you are a developer actively seeking Ruby interview preparation or a hiring specialist looking to bring Ruby developers to your company, the following list of Ruby interview questions will be very useful for you.

Here is the list of the best 2023 Ruby interview questions and answers. 👇💼

1. What are the standout features of the Ruby programming language?

Interpreted Language: Ruby is an interpreted programming language. Ruby code is directly interpreted and executed by the Ruby interpreter, which is in an executable format. This allows Ruby's code to be developed more flexibly and quickly, while enabling immediate testing of the code without the need for a compilation process.
Dynamic and Flexible: Ruby can change code at runtime.
Open Source and Cross-Platform: Ruby is open source. Anyone can download Ruby for free from the official website. It can run on different operating systems.
Object-Oriented: Strings, numbers, values, and basic data in Ruby are objects.

2. What is the difference between raise/rescue and throw/catch in Ruby?

In the Ruby programming language, raise and rescue are structures used for exception handling, while throw and catch are used for controlling program flow .

✅ raise is used to indicate an error condition. When an error occurs, an exception is raised with raise, and this exception can alter the flow of the program.
✅ rescue is used to catch an error condition.

✅ throw, is used to change the program flow at a certain point.
✅ catch is used to catch and handle the value "thrown" by a throw statement.

3. What are variables in Ruby?

There are four types of variables in Ruby:

1️⃣ Global Variables: These variables can be used throughout the entire Ruby program. They start with $.

2️⃣ Class Variables: Cover all instances of the defined class. These variables start with @@.

3️⃣ Local Variables: They cover the function or code structure in which they are declared. These variables start with a lowercase letter or an underscore.

4️⃣ Instance Variables: They represent data belonging to instances of a class. These variables start with @.

4. What are the different operators used in Ruby?

There are many operators in Ruby. Some of the most commonly used operators are:

• Arithmetic Operators

• Comparison (relational) Operators

• Assignment Operators

• Logical Operators

• Bitwise Operators

• Conversion Operators

• Equality (identity) Operators

5. What are the different class libraries used in Ruby?

Text processing
CGI Programming
Network programming
GUI programming
XML Programming

6. What are the data types used in Ruby?

The data types in Ruby represent different kinds of data such as text, strings, numbers, etc.

✔️ Numbers: Numeric data types represent integers and decimal numbers. For example; “5”, “3.14”

✔️ Strings: Strings represent text data such as a sentence or a word. String variables are defined by enclosing them in single (“”) or double (“”) quotes. Both single and double quotes can be used to create strings.

✔️ Symbols: They represent a single value symbolically.

✔️ Hashes: They are used to store key-value pairs. Each key represents a value. A key's value is assigned with the => symbol.

✔️ Arrays: They are used to store multiple values in an ordered manner. They can contain any type of data. The data in an array is separated by commas and enclosed in square brackets.

✔️ Booleans: They represent true or false values. They are used in conditional statements .

7. When is the “super” keyword used in Ruby?

🔐 The “super” keyword is used to call a method with the same name as the method that called it in the superclass.

8. What are Block, Proc, and Lambda in Ruby?

🎯 Block

It is the most basic structure used to create a code block. It is enclosed using the do/end keywords or parentheses {} . It can have multiple independent variables. The names of the independent variables are defined between two vertical lines .

🎯Proc

They are used to store block codes as objects and call them. They can be created using the Proc.new or proc keywords. They are also called using the call method.

🎯 Lambda

Lambda is a special Proc object. It is defined using -> or the lambda keyword.

9. What is interpolation in the Ruby programming language?

Interpolation is a very important process in Ruby. String interpolation means directly embedding variables or expressions within a string.

10. Why is Ruby known as a flexible language?

Ruby is known as a flexible language because it allows developers to modify parts of the language. Some aspects of the language can be removed or redefined. Ruby imposes no restrictions on the user. For example, to add two numbers, Ruby allows you to use either the + sign or the word 'plus'.

11. What is Rails Migration?

Rails Migration is a tool that allows developers to use Ruby to change the database schema. In other words, Ruby code is used instead of SQL. Rails Migration can do the following:

✔️ Create tables

✔️ Rename columns

✔️ Modify columns

✔️ Remove columns

✔️ Rename tables

✔️ Add columns

12. What is a Rails Controller?

In the Ruby on Rails framework, a Controller is a component that handles user requests in web applications and generates the appropriate responses.

13. What are the naming conventions in Ruby?

✅ Variables: All variables are written in lowercase letters and words are separated by underscores. For example: user_name
✅ Classes and Modules: Each word starts with a capital letter and underscores are not used.
✅ Database Tables: Database table names are written in lowercase letters and underscores are used between words. All table names should be in plural form. For example: users
✅ Models: Model names are always written in singular form.
✅ Controllers: Controller names are used in plural form and the word "Controller" is appended at the end. For example: OrdersController