Ruby on Rails Coding Interview Question: Reverse a String

4 min readMay 21

Preparing for a Ruby on Rails coding interview may be a stressful commitment. With the correct information and practice, though, you can confidently demonstrate your skills and obtain your desired job. I present a detailed list of frequent Ruby on Rails coding interview questions in this blog article to help you prepare efficiently.

I encourage readers to practice coding challenges, review the Rails documentation, and seek additional resources to enhance their understanding of Ruby on Rails. Armed with this knowledge, you’ll be well-equipped to excel in Ruby on Rails coding interviews and secure your desired position in web development.


Write a Ruby method to reverse a string.

Solution 1:

Here’s a Ruby method that reverses a string using built-in methods:

def reverse_string(str)

puts reverse_string("Hello, world!") #=> "!dlrow ,olleH"

This method makes use of Ruby’s String class’s reverse method. It returns the reversed version of the supplied string directly.

Time Complexity

The reverse method typically has a time complexity of O(n), where n is the length of the input string. It iterates over the characters of the string and creates a new reversed string.

Space Complexity

The space complexity of the reverse_string method is O(n) as well. When the reverse method is called, it creates a new string object that contains the reversed version of the input string. The space required to store the reversed string is proportional to the length of the input string.

Solution 2:

To reverse a string without using any built-in methods, use a method similar to the one described above:

def reverse_string_without_builtin(string)
reversed = ""
length = string.length

(length - 1).downto(0) do |i|
reversed += string[i]


puts reverse_string_without_builtin("Hello, world!") #=> "!dlrow ,olleH"

This method follows the same logic as before. It initializes an empty string called reversed, gets the length of the input…


Consultant | Freelancer | Ruby on Rails | ReactJS

Recommended from Medium


See more recommendations