regex.md

Practice sites

• RegEx 101 - Handles PCRE (PHP), JavaScript, and Python
• RegExr - Lets you test replacing using capture groups. Cannot handle lookbehinds b/c JavaScript only
• regex one - Has lessons

RegEx metachars and symbols

Metachar	Meaning
\n	newline
\w	word char [a-zA-Z0-9_]
\W	not word char
\d	digit
\s	space
^	start of string
$	end of string
.	any char except newline
*	0 or more of prev expression
+	1 or more of prev expression
?	make prev expression optional
`	`
{...}	explicit quantifier {2}, {2,5}
[...]	explicit set of chars
[^...]	exclude explicit set of chars
(...)	capturing group
(?:...)	don't create capturing group
(?=)	positive lookahead
(?!)	negative lookahead
(?<=)	positive lookbehind
(?<!)	negative lookbehind