RegEx Cheatsheet

Overview

RegEx patterns are made up of characters, groups and ranges:

Characters: match a single character
Group: match all chracters in group (AND)
Range: match any character in range (OR)

Characters

RegEx	Meaning
`.`	Anything except `\n`, `\r`. Means literal dot in `[]`
`\d`	Digit
`\D`	Not digit
`\s`	Whitespace (tab, space, newline, etc.)
`\S`	Not whitespace
`\w`	`[A-Za-z0-9_]`
`\W`	`[^A-Za-z0-9_]`
`\t`, `\r`, `\n`	Normal meanings
`$`	end of string
`^`	start of string

Quantifiers

RegEx	Meaning
`x?`	0 or 1 time
`x{a,b}`	`x` between `a` and `b` times (inclusive)
`x+`	1 or more
`x*`	0 or more
`x<quantifier>?`	Non-greedy match (as little string as possible)
`$`	end of string

Lookahead / Lookbehind

RegEx	Meaning
`x(?=y)`	match x if x is followed by y
`x(?!y)`	match x if x is not followed by y
`x(?<=y)`	match x if x is preceded by y
`x(?<!y)`	match x if x is not preceded by y

Groups and Ranges

RegEx	Meaning
`x\|y`	x or y (default global group, use inside group / range)
`[<characters>]`	match any enclosed character
`[^<characters>]`	match any non-enclosed character
`(x)`	capturing group, use via `$1, ..., $9`
`\n`	backreference to group `n`
`(?:x)`	non-capturing group

See here on how to display | inside a Markdown table.