R Regex Cheat Sheet

Here’s a R regex cheat sheet for using regular expressions in R:

Basics

Matching a Pattern:

grepl("pattern", text)

Extracting Matches:

regmatches(text, gregexpr("pattern", text))

Anchors and Quantifiers

Start of Line:

"^pattern"

End of Line:

"pattern$"

Zero or More Occurrences:

"a*"

One or More Occurrences:

"a+"

Optional (Zero or One):

"a?"

Character Classes

Any Digit:

"\\d"

Any Word Character:

"\\w"

Any Whitespace Character:

"\\s"

Negation:

"[^0-9]"

Quantifiers

Exact Number of Occurrences:

"a{2}"

Range of Occurrences:

"a{2,4}"

Groups and Alternation

Grouping:

"(abc)+"

Alternation:

"cat|dog"

Escape Characters

Escape Special Characters:

"\\."

Escape Metacharacters:

"\\(\\[\\{"

Modifiers

Case Insensitive:

"(?i)pattern"

Multiline Mode:

"(?m)pattern"

Anchors

Word Boundary:

"\\bword\\b"

Negative Word Boundary:

"\\Bword\\B"

This cheat sheet covers some commonly used regex patterns and constructs in R. Regular expressions in R follow the POSIX syntax, and the grep, grepl, regexpr, and regmatches functions are commonly used for regex operations. Feel free to refer to the R documentation on regular expressions for more details and advanced usage.