RegEXP

Regular expressions

Special Characters

. [ { ( ) \ ^ $ | ? * +

symbol	function	example
`\`	Escape symbol - makes the next character literal	`\.` dot `\*` star `\\` backslash

General tokens

symbol	function	example
`\n`	Newline
`\N`	Anything but a newline
`\t`	Tab
`\0`	Null character

Meta sequences

symbol	function	example
`.`	Any single character other than newline (or including line terminators with the /s flag)	`/.+/` = a b c
`a\|b`	a OR b
`\s`	Any whitespace
`\S`	Any non-whitespace
`\d`	Any digit
`\D`	Any non-digit
`\w`	Any word character
`\W`	Any non-word character
`\h`	Horizontal whitespace character
`\r`	Carriage return
`\R`	Unicode newlines

Character classes

symbol	function	example
`[abc]`	A single character of a b c
`[^abc]`	A character except a b c
`[a-zA-Z]`	A character in range a - z or A-Z
`[a-z]`	A character in range a - z
`[^a-z]`	A character not in range a - z
`[[:<:]]`	Start of word. POSIX equivalent of the `\b` (word boundary) is interpreted as `\b(?=\w)`
`[[:>:]]`	End of word. POSIX equivalent of the `\b` word boundary is interpreted as `\\b(?<=\\w)`
`[[:alnum:]]`	Letters and digits. Equivalent to `[A-Za-z0-9]`
`[[:alpha:]]`	Letters. Equivalent to `[A-Za-z]`.
`[[:[[TXT file]]:]]`	ASCII codes 0 - 127. Equivalent to `[\x00-\x7F]`
`[[:blank:]]`	Space or Tab only (not new lines). Equivalent to `[ \t]`
`[[:word:]]`	Word character, letters, numbers, underscores. POSIX equivalent to `\w` or `[a-zA-Z0-9_]`
`[[:punct:]]`	Matches characters that are not whitespace, letters or numbers.

Quantifiers

symbol	function	example
`a?`	Zero or one of a.	`.?` = Zero or one any characters
`a*`	Zero or more of a. Greedy quantifier - matches as many characters as possible
`a+`	One or more of a
`a{3}`	Exactly 3 of a
`a{3,}`	3 or more of a
`a{3,6}`	Between 3 and 6 of a
`a*?`	Lazy quantifier - matches as few characters as possible
`a*+`	Possessive quantifier

Anchors

symbol	function	example
`\b`	A word boundary
`\B`	Non-word boundary
`^` or `\A`	Start of string
`$` or `\Z`	End of string
`\z`	Absolute end of string

Groups

symbol	function	example
`(?: ...)`	Match anything enclosed
`(...)`	Capture anything enclosed

Substitution

symbol	function	example
`$1`	Contents of capture group 1
$`	Contents before match
$'	Contents after match
$&	Complete match content
`\x20`	Hexadecimal replacement values
`\x{06fa}`	Hexadecimal replacement values
`\t`	Insert Tab
`\r`	Insert carriage return
`\n`	Insert Newline
`\f`	Insert form-feed

Character Escapes

symbol	code	meaning
`\a`	\u007	bell
`\b`	\u008	Backspace
`\t`	\u009	Tab
`\r`	\u00D	CR
`\v`	\u00B	Vertical tab
`\f`	\u00C	Formfeed
`\n`	\u00A	NL
`\e`	\u001B	Escape
`\nNN`		Octal character
`\xNN`		Hex character
`\uNNNN`		Unicode character

Modifiers

symbol	function	example
g	Global
m	Multiline
i	Case sensitive
u	Unicode
U	Ungreedy
x	Ignore whitespace/verbose

Useful ones

Get array content without parenthesis per word

(?:\[([^\]]+)\]) /gm

Extract json to csv

*"(\w+)": "?(\w*)"?,/gm

MySQL : table structure parser

^(\w+)\s+(\w+)(\(\d*\))?.*$

Match an email address

^\w{4,}@+\w{2,}(.com|.co.uk|.net|.info|.xyz)$ gm

Regex of email with ability to add gmail's +example system
root email = user@gmail.com gmail+ = user+extra@gmail.com

^[a-zA-Z0-9_.]+[+]?[a-zA-Z0-9]+[@]{1}[a-z0-9]+[\.][a-z]+$ /gm

RFC 2822 Email validation

[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])? /g

IP4 address

\b(?:(?:2(?:[0-4][0-9]|5[0-5])|[0-1]?[0-9]?[0-9])\.){3}(?:(?:2([0-4][0-9]|5[0-5])|[0-1]?[0-9]?[0-9]))\b /ig

IP proxy scrap

\b(?:(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9]))|\:(\d*)\b /g

Match an IPv6 address

^(?1)){1,6}$ /gmi

^(?:[[:xdigit:{1,4}:){5}:(?:[[:xdigit:{1,4}:){1,6}:$ /gm

Detect script tag

<.*?script.*\/?> /ig

Phone number

^\s*(?:\+?(\d{1,3}))?([-. (]*(\d{3})[-. )]*)?((\d{3})[-. ]*(\d{2,4})(?:[-.x ]*(\d+))?)\s*$ /gm

Youtube URL

(?:https?:\/\/)?(?:(?:(?:www\.?)?youtube\.com(?:\/(?:(?:watch\?.*?(v=[^&\s]+).*)|(?:v(\/.*))|(channel\/.+)|(?:user\/(.+))|(?:results\?(search_query=.+))))?)|(?:youtu\.be(\/.*)?))

Makdown link

(\[((?:\[^\[\)*)\]\([ \t]*()<?((?:\([^)]*\)|[^()\s])*?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\)) /g

JS Comment

\/\/(?![\S]{2,}\.[\w]).*|\/\*(.|\n)+?\*\/ /g

Trim whitespace

(?:\s)\s /g

Hex color

\b0x(?:[0-9A-Fa-f]{6}|0-9A-Fa-f]{8})\b