Introduction to R

R is a programming language built for statistics and data analysis — it lets you load data, compute summaries, run statistical models, and draw publication-quality charts with very little code.

Learn Introduction to R in our free R course — a beginner-friendly interactive lesson with worked examples, a practice exercise and a quick reference.

Part of the free R course at LearnCodingFast — hands-on lessons with examples you run in your browser, plus practice exercises and a quick quiz.

By the end of this lesson you'll understand what R is and why analysts love it, how to use R as a calculator, how to store values in variables, and you'll have run your own first lines of R code.

What You'll Learn in This Lesson

1️⃣ Your First Lines of R

In R you don't need a main() function or any boilerplate. You type an expression and R evaluates it. To keep a value around for later, you assign it to a name with the operator (read it as "gets"). Read the worked example below — every line is explained — then run it yourself.

Notice the [1] in front of each result. That's not an error — it's R telling you the output starts at the first element. Because R treats even a single number as a one-element vector , every printed result carries an index. You'll see why that matters in the Vectors lesson.

2️⃣ R as a Calculator with Memory

R shines as an interactive calculator. You can do arithmetic directly, store intermediate results in variables, and call built-in functions using the name(arguments) pattern. The c() function ("combine") builds a vector — the structure R is built around.

In one line — mean(scores) — R averaged four numbers at once. That "do it to the whole collection" style is the heart of R and is what makes data analysis so concise.

3️⃣ Types and Getting Help

Every value in R has a type, which you can inspect with class() . When you're unsure how a function works, R's built-in help is excellent — type ?mean to open the documentation for mean .

Your turn. The script below works once you fill in the two # TODO blanks. Follow the hints, then run it and compare with the expected output.

No blanks this time — just a brief and an outline. Write it yourself, run it, and check your output against the example in the comments. Tiny programs like this build real fluency fast.

📋 Quick Reference — R Basics

Practice quiz

• Browse all free courses
• Cheat sheets & quizzes
• Coding dictionary