R Academy · Lesson

Regular Expressions

Leverage pattern matching and substitution with regex for complex text handling tasks.

Lesson 2 of 310 steps

Regular Expressions is a free R Academy lesson on CoddyKit. This is lesson 2 of 3. Any 3 lessons of this learning path are free to read in full — after that, CoddyKit PRO unlocks every lesson, plus hands-on practice with a built-in code editor and a 24/7 AI tutor. It is part of the R Academy learning path, and your progress syncs across the web and the CoddyKit app. The R Academy course includes 3 lessons in total.

Introduction to Regular Expressions in R

Regular expressions (regex) allow you to match and manipulate text patterns efficiently. In this lesson, you'll learn the basics of using regex in R.

Using grep() to Find Patterns

The grep() function searches for patterns in a vector.

text <- c('apple', 'banana', 'cherry')
grep('a', text)

Using grepl() to Check for Patterns

The grepl() function returns TRUE or FALSE if a pattern is found.

grepl('a', text)

Extracting Matches with regexpr()

The regexpr() function locates the first occurrence of a pattern in a string.

regexpr('an', 'banana')

Using gsub() for Replacement

The gsub() function replaces all occurrences of a pattern in a string.

gsub('a', '@', 'banana')

Using sub() for First Match Replacement

The sub() function replaces only the first occurrence of a pattern.

sub('a', '@', 'banana')

Using str_extract() for Pattern Extraction

The str_extract() function from stringr extracts matched patterns.

library(stringr)
str_extract('abc123', '\d+')

Using str_replace_all()

The str_replace_all() function replaces multiple matches using stringr.

library(stringr)
str_replace_all('banana', 'a', '@')

Summary

In this lesson, you learned:

How to find patterns using grep() and grepl().
How to extract and replace patterns in text.
How to use stringr for advanced regex operations.

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Frequently Asked Questions

Is the “Regular Expressions” lesson free?

Yes — any 3 lessons of the R Academy learning path, including “Regular Expressions”, are free to read in full here on the web. After that, CoddyKit PRO unlocks every lesson, plus interactive practice with a built-in code editor and a 24/7 AI tutor. The R Academy course includes 3 lessons in total.

What will I learn in “Regular Expressions”?

Leverage pattern matching and substitution with regex for complex text handling tasks. You practise R Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start R Academy?

No prior experience is required. R Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 3.

How long does the “Regular Expressions” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this R Academy lesson?

Yes. Every R Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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