DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports Events Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones AWS Cloud
by AWS Developer Relations
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Partner Zones
AWS Cloud
by AWS Developer Relations

Trending

  • How AMD's Heterogeneous Systems Architecture Works, and Why
  • Orchestration Pattern: Managing Distributed Transactions
  • How To Integrate Microsoft Team With Cypress Cloud
  • How To Use Pdb to Debug Common Python Errors

Day 13 of 30 Ruby Coding Challenge - Fibonacci Sequence in Ruby

Day 13 of 30. We're going to solve the famous Fibonacci sequence in Ruby. The next videos are going to be all about getting the algorithm better

Alexandre Gama user avatar by
Alexandre Gama
·
Jul. 06, 20 · Tutorial
Like (1)
Save
Tweet
Share
3.32K Views

Join the DZone community and get the full member experience.

Join For Free

Hey friends!

This is the blog post version of the Youtube video from the 30 Ruby Coding Challenges in 30 Days series

Fancy Fibonacci Algorithm Definition

  • To get the next number in a sequence, you have to sum the previous two numbers.

One important point: The Fibonacci sequence already starts with 0 and 1 as the first 2 numbers

Here is a sequence to help you out a bit more:

Plain Text
 




x


 
1
0 1 1 2 3 5 8 13 21 34 55 88 ...



Perfect. Now we want to solve the following puzzle:

We want to calculate the first N numbers in a Fibonacci sequence

First Real Example:

I want to calculate the first 8 numbers in a Fibonacci sequence:

Plain Text
 




xxxxxxxxxx
1


 
1
0 1 1 2 3 5 8 13



Second Real Example:

I want to calculate the first 10 numbers in a Fibonacci sequence:

Plain Text
 




xxxxxxxxxx
1


 
1
0 1 1 2 3 5 8 13 21 34



I’m pretty sure you got it : )

Fibonacci Algorithm in Ruby

Step 1

  • let’s create the fibonacci() method
  • then we’ll start the sequence with 0 and 1
Ruby
 




xxxxxxxxxx
1


 
1
def fibonacci(count)
2
  n1 = 0
3
  n2 = 1
4
  sequence = [n1, n2]
5
end
6

          
7
puts fibonacci(8)



Step 2

  • because the list starts with 2 numbers, we can calculate the next one using a while loop
Ruby
 




xxxxxxxxxx
1
12


 
1
def fibonacci(count)
2
  n1 = 0
3
  n2 = 1
4
  sequence = [n1, n2]
5
  while count > 2 # just a while loop expression that decrements the argument count
6
    count = count - 1
7
  end
8
  return sequence
9
end
10

          
11
puts fibonacci(8)
12
# 0 1 1 2 3 5 8 13



Step 3

  • the next number is the sum of the previous 2 numbers
Ruby
 




xxxxxxxxxx
1
19


 
1
def fibonacci(count)
2
  n1 = 0
3
  n2 = 1
4
  sequence = [n1, n2]
5
  while count > 2
6
        # sum of the previous 2 numbers
7
    n3 = n1 + n2
8
    sequence.push(n3)
9
10
      # assigning the new numbers to calculate the next number in the sequence
11
    n1 = n2
12
    n2 = n3
13
    count = count - 1
14
  end
15
  return sequence
16
end
17
18
puts fibonacci(8)
19
# 0 1 1 2 3 5 8 13



Pretty simple, isn’t it?

Although the code is simple, it’s far from a good code design because:

  • it lacks readability
  • it updates an argument received in the method
  • it has too many local variables

To be honest, sometimes (and even most of the time), a good code design is a matter of context and personal taste, and maybe you might think that this code is already good enough, and I don’t blame you. However, I’ll solve the same problem using a different approach that probably you might like better


Hope to see you in the next Ruby Coding Challenge : )

Don’t forget to come by and say hi Alex
Courses Twitter Youtube Instagram Linkedin GitHub

Coding (social sciences) Plain text

Published at DZone with permission of Alexandre Gama. See the original article here.

Opinions expressed by DZone contributors are their own.

Trending

  • How AMD's Heterogeneous Systems Architecture Works, and Why
  • Orchestration Pattern: Managing Distributed Transactions
  • How To Integrate Microsoft Team With Cypress Cloud
  • How To Use Pdb to Debug Common Python Errors

Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com

Let's be friends: