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Learn R Programming

A free, interactive online R course. You write R on every lesson, with AI hints when a factor surprises you, and a free certificate when you finish.

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View syllabusR playground

21,395+ codders enrolled

199 lessons178 challenges1,112 quiz questions

  • Beginner friendly
  • sparkles iconAI-assisted coding help
  • hint iconHands-on interactive lessons
  • volume On iconAudio narration on every lesson
  • quiz iconQuizzes to test your knowledge
  • certificate iconFree certificate of completion

Syllabus

3 sections5 projects199 lessons178 challenges1,112 quiz questions
  1. Section 1

    Fundamentals

    Start sectionStartExpandCollapse    Build a strong foundation with essential concepts and basic skills78 lessons75 challenges432 questions2 projects

    Introduction to R

    3 lessons616

    Variables and Data Types

    8 lessons956

    Operators Part 1

    5 lessons534

    Operators Part 2

    5 lessons534

    Decision Making

    4 lessons425

    Basic IO

    7 lessons741

    Bill Split Calculator

    Project5 lessons1

    Loops

    8 lessons848

    Functions

    6 lessons633

    FizzBuzz with a Twist

    Project4 lessons1

    Vectors

    7 lessons742

    Iterating Over Sequences

    4 lessons433

    Vectors Advanced

    4 lessons436

    Lists in R

    5 lessons534

    Final Challenges

    3 lessons3
  2. Section 2

    Logic & Flow

    Start sectionStartExpandCollapse    Build on R Fundamentals with string tools, lookups, sets, matrices, the apply family, sorting and grouping, data frames, advanced control flow and error handling. Apply your skills in Gradebook and Expense Tracker projects, mastery and final challenges.64 lessons97 challenges344 questions2 projects

    Strings In Depth

    6 lessons1140

    Key-Value Lookups

    5 lessons932

    Sets and Counting

    5 lessons932

    Matrices

    5 lessons932

    Project - Gradebook

    Project5 lessons18

    Functions as Values

    5 lessons932

    The Apply Family

    5 lessons932

    Sorting and Grouping

    5 lessons932

    Data Frames

    5 lessons932

    Advanced Control Flow

    5 lessons932

    Error Handling

    5 lessons932

    Project - Expense Tracker

    Project5 lessons18

    Final Challenges

    3 lessons3
  3. Section 3

    Object Oriented Programming

    Start sectionStartExpandCollapse    Model programs with R's object systems. Learn S3 classes, constructors, generics and inheritance, closures and environments that keep state, S4 classes, generics and validity, Reference Classes and classic design patterns, then build a Library Management project.57 lessons94 challenges336 questions1 project

    S3 Basics

    6 lessons1140

    S3 Generics and Methods

    5 lessons932

    S3 Inheritance

    5 lessons932

    Encapsulation in R

    5 lessons932

    S4 Classes

    5 lessons932

    S4 Generics and Methods

    5 lessons932

    S4 Inheritance

    5 lessons932

    Reference Classes

    5 lessons932

    Design Patterns Part 1

    4 lessons832

    Design Patterns Part 2

    4 lessons832

    Project: Library Management

    Project5 lessons18

    Final Challenges

    3 lessons3

R courses

Hands-on R courses, free to start in your browser.

Interview PreparationData StructuresGraph Algorithms Courses

Beginner Challenges - Practice Basic Concepts

Popular

Put your beginner coding knowledge to test and try to solve this programming challenges, use any language you want, Happy Coding!

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Certificate on completion

  • 20
  • 20

Coding Problems

Popular

Put your programming problem solving skills to the test using the exercises with different difficulties in this course. Designed for coders with some prior knowledge of the basic syntax in any programming language.

certificate icon

Certificate on completion

  • 32
  • 31

Stack - Data Structures Series #1

In this course, you will learn about the Stack data structure, create a Stack from zero using your preferred language, and practice coding challenges with it!

Data Structures
  • 13
  • 6
  • 1

AVL Tree - Data Structures Series #10

In this course, you will learn about the AVL Tree data structure, build a self-balancing binary search tree from zero in your preferred language, and practice coding challenges with it!

Data Structures
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Certificate on completion

  • 16
  • 6
  • 1

Interview Coding Challenges - Pack I

Are you ready for your next coding interview? Test your knowledge and skills with these challenges and be prepared. Good luck!

Interview Preparation
  • 3
  • 3

Star Pattern Bootcamp

Put your programming problem solving skills to learn how to print star patterns range from simple to complex, involving different levels of nested loops, conditional statements, and mathematical calculations.

  • 30
  • 28
See all 44 R courses →
What you get
Everything you'll use to learn to code

Learn by Doing

Write real code, query databases, build websites, and master AI prompts. Our interactive lessons cover every skill modern developers need.

playground.js
Code Editor
1const greeting = "Hello, Coddy!"
2function sayHi(name) {
3    return greeting + " " + name
4}
5
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Input
"Alex"
Output
"Hello, Coddy! Alex"

Build Your Streak

Stay consistent and watch your progress grow! Track your daily coding habit, protect your streak with freeze days, and earn rewards for showing up every day.

12 days streak

Return tomorrow to keep your streak!

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January 2026

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Double or Nothing

Day 5 of 7

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Streak Freeze

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Code Anywhere

Take your coding journey on the go! No setup, no downloads - just open and start coding. Available on iOS, Android and Web with 4.9 star ratings.

Python
7Streak
250Score
5Energy
Variables
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CONTINUE
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Journey
Goals
Leaderboard
Profile
4.9
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Rating

You're Not Alone

Compete on global leaderboards, invite friends to earn rewards, and celebrate each other's wins. Coding is better with friends!

Challenger League
Challenger LeagueTop 7 advance
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Alex7+ Days
2840
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Jordan7+ Days
2650
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Sam7+ Days
2420
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Casey
2180
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Morgan7+ Days
1950
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Every way to learn

Read, listen, test yourself, ask the AI, or look up anything you've already covered. Every lesson meets you where you are.

Intro to Variables
Audio

A variable is a named container that stores a value you can reference later in your program.

In Python, you create one by writing the name, an equals sign, then the value you want to store.

The value can change over time - reassigning the name simply points it to a new value.

1xSarah

Earn a Certificate

Earn certificates for every course you complete. Add them to your LinkedIn profile and resume to showcase your coding expertise to employers.

CoddyCertificate of Completion
This certifies thatJohn Doehas successfully completed
python iconPython Fundamentals
Verified
DateJan 2026
LinkedInAdd to LinkedIn

Why learn R with Coddy

  • Run real R code in your browser. No R install, no RStudio setup. Each lesson runs your R script server-side and shows the output, including printed values and basic plots, instantly.
  • R as it's actually used for data: vectors and lists, data frames, indexing and filtering, functions, the apply family, basic statistics, and reading and summarizing data. The R foundations every analyst and data scientist needs.
  • AI hints help you fix R errors and read cryptic warning messages without spoiling the answer, so common stumbles like factor surprises and recycling rules become learning moments.
  • Free R programming certificate when you finish the course. A credible signal for analyst, data-science, and statistical-research roles where R fluency is a baseline expectation.

Frequently asked questions about learning R

Is R hard to learn?

R has a few quirks that throw newcomers - 1-based indexing, vectorized operations, factors - but the core is straightforward, especially for anyone who's worked with spreadsheets before. The course introduces R in small steps with hands-on exercises, so the quirks feel like features rather than traps.

What is R programming used for?

R is the lingua franca of statistics, data analysis, and academic research. Heavily used in bioinformatics, econometrics, social sciences, finance, and any field where you need to load data, run statistical models, and produce charts. The package ecosystem around R (especially the tidyverse and ggplot2) is one of its biggest strengths.

How long does it take to learn R?

R basics - variables, vectors, data frames, basic plotting - take one to two weeks of daily practice. Becoming comfortable with data wrangling, statistical models, and ggplot2 usually takes one to three months. Domain depth (bioinformatics, finance, social science) is then layered on top through real projects.

Should I learn R or Python for data science?

Both work. R was built for statistics and stays unmatched for statistical modeling, academic work, and exploratory analysis. Python is the more general-purpose choice with stronger machine-learning and engineering ecosystems. Many data scientists know both and pick per task; if you're statistics-first, start with R.

Can I learn R online for free?

Yes. The interactive R course is free - full lessons, R coding exercises, quizzes, and a certificate. R runs server-side so you don't need to install R or RStudio locally to start writing code.

Do I get a certificate after the R course?

Yes. Finishing the R programming course gives you a free certificate of completion. A verifiable proof point you can add to your resume or share on LinkedIn alongside any analysis projects or notebooks you've built.

Learning paths that include this course

This course is one step of a longer path: several courses in the order a mentor would teach them, each with its own free certificate.

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Learn R with Coddy

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