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Ruby for complete beginners
RubyConf Africa 2026, Keynote
OKURA Masafumi, 2026-08-22
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Jambo!
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Jina langu ni
Masafumi
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1
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23
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3
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3
2019
2024
2026
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3
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3 important questions
• What is programming?
• How can we get better at programming?
• Why is Ruby good for beginners?
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self.introduction
• Name: OKURA Masafumi (Masafumi is my rst name)
• Title: Freelance software developer
• Works/Activities: Authoring Alba gem (JSON serializer), founding of
Kaigi on Rails (a Rails conference in Tokyo)
• Likes: Coffee, joining conferences (RubyConf Africa is the 7th Ruby
fi
conference I’ve attended this year so far)
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What is
programming?
1.
2.
3.
What is programming?
How can we get better
at programming?
Why is Ruby good for
beginners?
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What is
programming?
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Writing code?
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❌Writing code
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⭕Making
abstract things
more concrete
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Abstract / Essential / Valuable
• Ideas
• Intentions
• Thoughts
• Businesses
• Logics
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Concrete / Non-essential / Less-valuable
• Implementations
• Code
• Classes
• Functions
• Documents
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Example:
Anagram check
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e.g. anagram check
Abstract
• We want to check if two words
are anagrams or not
Concrete
• Strip each word, make each
word down case, sort each
word and check if they are
equal
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Another example:
e-commerce
website
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e.g. What E-commerce sites do?
Abstract
• We want to sell things
• Payment system
• We want to communicate with
• Noti cations system
customers
• We want to store customer data
fi
Concrete
• Database for customers storing
name, address, etc.
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e.g. What E-commerce sites do?
Still Abstract
• Payment system
• Stripe and its client library
• Noti cations system
• Email delivery with Sendgrid
• Database for customers storing
• PostgreSQL server with a
name, address, etc.
fi
More Concrete
schema
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Making abstract
things more
concrete
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Why?
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Computers can
do concrete
things only
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Human interaction
Application
Library
OS / Middleware
Hardware
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Gradual
translation
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Human interaction
Application
Library
OS / Middleware
Hardware
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Abstraction
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Human interaction
Rails Application
Rails, pg gem
Linux, Ruby, Postgres
CPU
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Why?
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Humans are
better at abstract
things
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Programming is
translation
between humans
and computers
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How can we get
better at
programming?
1.
2.
3.
What is programming?
How can we get better
at programming?
Why is Ruby good for
beginners?
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How can we get
better at
programming?
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I’m a translator
😏
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How can we get
better at
translation?
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Japanese: 🤩
English: 😎
Vim/Neovim: 💪
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Being good
enough at 3
things
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• Target language
• Original language
• Vim/Neovim
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• Computer language
• Human language
• Problem domain
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English
Japanese
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English
Intermediate ideas
Japanese
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Understanding
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English
Understanding
Intermediate ideas
Japanese
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English + Vim/Neovim
Understanding
Intermediate ideas
Japanese
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English + Vim/Neovim
Understanding
Intermediate ideas
Expressiveness
Japanese
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Expressiveness
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Problem domain expressed
in human language
Understanding
Intermediate ideas
Expressiveness
Software product
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Being expressive
with computer
language
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Being expressive
with Ruby
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How can we get better at programming?
• Understanding things well
• Being familiar with problem domain
• Being expressive
• Being familiar with computer languages
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Why is Ruby
good for
beginners?
1.
2.
3.
What is programming?
How can we get better
at programming?
Why is Ruby good for
beginners?
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Ruby for complete beginners
RubyConf Africa 2026
OKURA Masafumi, 2026-08-22
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Ruby for complete beginners
RubyConf Africa 2026
OKURA Masafumi, 2026-08-22
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Why is Ruby
good for
beginners?
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Understanding
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How do we
understand
something?
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Trials and errors
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❌0 -> 100
⭕0 -> 10 -> 20… 100
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How do we
understand the
problem?
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Trials and errors
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Gradual
understanding
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How can we
gradually
program?
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Exploratory
Programming
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New concept: Exploratory Programming
1. Write code to solve problems (which might be real problems)
2. Understanding problems better by observing code and its
behavior
3. Go back to 1 until we are sure we understand problems well
enough
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The goal is
not code
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The goal is
understanding
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Why is Ruby good
at Exploratory
Programming?
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fi
Example:
Anagram nder
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Ruby’s strengths
• Powerful stdlib: `combination`, `group_by`, `strip`, etc. When you
need it, there it is.
• Powerful ecosystem: Rails offers even more vocabularies. It extends
builtin classes so it feels natural as if it existed from the beginning.
• Powerful expressiveness: It expresses what it does, not how it does.
With method chains, it reads as English.
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Another
example:
Alba
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Ruby is a
framework for
thinking
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Ruby is a
framework for
understanding
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Ruby is a
framework for
expressing
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Let’s build things
with Ruby
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Let’s build things
with Ruby so that
we are better
programmers
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