Regex Python Cheat Sheet

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.Default: Match any character except newline.DOTALL: Match any character including newline^

POPULAR PYTHON RE MODULE FUNCTIONS re.findall(A, B) Matches all instances of an expression A in a string B and returns them in a list. Data Science Cheat Sheet Python Regular Expressions LEARN DATA SCIENCE ONLINE Start Learning For Free - www.dataquest.io LEARN DATA SCIENCE ONLINE. Pythex is a quick way to test your Python regular expressions. Try writing one or test the example. Match result: Match captures: Regular expression cheatsheet Special characters escape special characters. Matches any character ^ matches beginning of string $ matches end of string 5b-d. Python Regex Cheat Sheet Last Updated: 24 Jan, 2021 Regex or Regular Expressions are an important part of Python Programming or any other Programming Language. It is used for searching and even replacing the specified text pattern. Regular Expressions Cheat Sheet by DaveChild - Cheatography.com Created Date: 4237Z.

Default: Match the start of a string^MULTILINE: Match immediatly after each newline$Match the end of a string$MULTILINE: Also match before a newline*Match 0 or more repeti­tions of RE+Match 1 or more repeti­tions of RE?Match 0 or 1 repeti­tions of RE*?, *+, ??Match non-greedy as few characters as possible{m}Match exactly m copies of the previous RE{m,n}Match from m to n repeti­tions of RE{m,n}?Match non-greedyEscape special characters[]Match a set of characters|RE1|­RE2: Match either RE1 or RE2 non-greedy(...)Match RE inside parant­heses and indicate start and end of a groupWith RE is the resulting regular expression.
Special characters must be escaped with if it should match the character literally

Methods of 're' module

re.compile(
pattern,
flags=0)Compile a regular expression pattern into a regular expression object. Can be used with match(), search() and othersre.search(
pattern,
string,
flags=0Search through string matching the first location of the RE. Returns a match object or Nonere.match(
pattern,
string,
flags=0)If zero or more characters at the beginning of a string match pattern return a match object or Nonere.fullmatch(
pattern,
string

Regex Python Cheat Sheet

,
flags=0)If the whole string matches the pattern return a match object or Nonere.split(
pattern,
string,
maxsplit=0,
flags=0)Split string by the occurr­ences of patternmaxsplit times if non-zero. Returns a list of all groups.re.findall(
pattern,
string,
flags=0)Return all non-ov­erl­apping matches of pattern in string as list of strings.re.finditer(
pattern,
string,
flags=0)Return an iter­ator yielding match objects over all non-ov­erl­apping matches for the pattern in stringre.sub(
pattern,
repl,
string,
count=0,
flags=0)Return the string obtained by replacing the leftmost non-ov­erl­apping occurr­ences of pattern in string by the repla­cementrepl. repl can be a function.re.subn(
pattern,
repl,
string,
count=0,
flags=0)Like sub but return a tuple (new_string, number_of_subs_made)re.escape(
pattern)Escape special characters in patternre.p­urg­e()Clear the regular expression cache

Raw String Notation

In raw string notation r't­ext­' there is no need to escape the backslash character again.
>>> re.mat­ch(­r'W­(.)­1­W', ' ff ')
<r­e.Match object; span=(0, 4), match=' ff '>
>>> re.mat­ch(­'­W­(.)­1­W­', ' ff ')
<r­e.Match object; span=(0, 4), match=' ff '>

Reference

https:­//d­ocs.py­tho­n.o­rg/­3/h­owt­o/r­ege­x.htmlhttps:­//d­ocs.py­tho­n.o­rg/­3/l­ibr­ary­/re.html

Extensions

(?...)This is the start of an extension(?aiLmsux)The letters set the corres­pondig flags See flags(?:...)A non-ca­pturing version of regular parant­heses(?P<na­me>...)Like regular paranthes but with a named group(?P=name)A backre­ference to a named group(?#...)A comment(?=...)lookahead assert­ion: Matches if ... matches next without consuming the string(?!...)negative lookahead assert­ion: Matches if ... doesn't match next(?<­=....)positive lookbehind assert­ion: Match if the current position in the string is preceded by a match for ... that ends the current position(?<­!...)negative lookbehind assert­ion: Match if the current position in the string is not preceded by a match for ...(?(id/name)yes-pattern|no-pattern)Match with yes-p­attern if the group with gived id or name exists and with no-pa­ttern if not

Match objects

Match.expand(
template)Return the string obtained by doing backslash substi­tution on templ­ate, as done by the sub() methodMatch.group(
[group1,...])Returns one or more subgroups of the match. 1 Argument returns string and more arguments return a tuple.Match.__getitem__(
g)Access groups with m[0], m[1] ...Match.groups(
default=None)Return a tuple containing all the subgroups of the matchMatch.groupdict(
default=None)Return a dict­ion­ary containing all the named subgroups of the match, keyed by the subgroup name.Match.start(
[group]
Match.end(
[group])Return the indices of the start and end of the substring matched by groupMatch.span(
[group])For a match m, return the 2-tuple (m.start(group) m.end(group))Match.­posThe value of pos which was passed to the sear­ch() or matc­h() method of the regex objectMatch.­e­ndposLikewise but the value of endposMatch.­l­ast­indexThe integer index of the last matched capturing group, or None.Match.­l­ast­groupThe name of the last matched capturing group or NoneMatch.­reThe regular expression object whose matc­h() or sear­ch() method produced this match instanceMatch.­s­tringThe string passed to matc­h() or sear­ch()

Special escape characters

AMatch only at the start of the stringbMatch the empty string at the beginning or end of a wordBMatch the empty string when not at the beginning or end of a worddMatch any Unic­ode decimal digit this includes [0-9]DMatch any character which is not a decimal digitsMatch Unic­ode white space characters which includes [ tnr­fv]SMatches any character which is not a whitespace character. The opposite of swMatch Unic­ode word characters including [a-zA-­Z0-9_]WMatch the opposite of wZMatch only at the end of a string

Regular Expression Objects

Pattern.search(
string[,
pos[,
endpos]])See re.­sea­rch­(). pos gives an index where to start the search. endpos limits how far the string will be searched.Pattern.match(
string[,
pos[,
endpos]])Likewise but see re.­mat­ch()Pattern.fullmatch(
string[,
pos[,
endpos]])Likewise but see re.­ful­lma­tch­()Pattern.split(
string,
maxsplit=0)Identical to re.­spl­it()Pattern.findall(
string[,
pos[,
endpos]])Similar to re.­fin­dal­l() but with additional parameters pos and endposPattern.finditer(
string[,
pos[,
endpos]])Similar to re.­fin­dit­er() but with additional parameters pos and endposPattern.sub(
repl,
string,
count=0)Identical to re.­sub­()Pattern.subn(
repl,
string,
count=0)Identical to re.­sub­n()Patter­n.­fl­agsThe regex matching flags.Patter­n.­gr­oupsThe number of capturing groups in the patternPattern.groupindexA dictionary mapping any symbolic group names to group membersPatter­n.­pa­tternThe pattern string from which the pattern object was compiledThese objects are returned by the re.­com­pil­e() method

Flags

ASCII, AASCII-only matching in w, b, s and dIGNORECASE, Iignore caseLOCALE, Ldo a local-­aware matchMULTILINE, Mmultiline matching, affecting ^ and $DOTALL, Sdot matches alluunicode matching (just in (?aiLm­sux))VERBOSE, XverboseFlags are used in (?aiLmsux-imsx:...) or (?aiLmsux) or can be accessed with re.FLAG. In the first form flags are set or removed.
This is useful if you wish to include the flags as part of the regular expression, instead of passing a flag argument to the re.compile() function The tables below are a reference to basic regex. While reading the rest of the site, when in doubt, you can always come back and look here. (It you want a bookmark, here's a direct link to the regex reference tables). I encourage you to print the tables so you have a cheat sheet on your desk for quick reference.
The tables are not exhaustive, for two reasons. First, every regex flavor is different, and I didn't want to crowd the page with overly exotic syntax. For a full reference to the particular regex flavors you'll be using, it's always best to go straight to the source. In fact, for some regex engines (such as Perl, PCRE, Java and .NET) you may want to check once a year, as their creators often introduce new features.
The other reason the tables are not exhaustive is that I wanted them to serve as a quick introduction to regex. If you are a complete beginner, you should get a firm grasp of basic regex syntax just by reading the examples in the tables. I tried to introduce features in a logical order and to keep out oddities that I've never seen in actual use, such as the 'bell character'. With these tables as a jumping board, you will be able to advance to mastery by exploring the other pages on the site.

How to use the tables

The tables are meant to serve as an accelerated regex course, and they are meant to be read slowly, one line at a time. On each line, in the leftmost column, you will find a new element of regex syntax. The next column, 'Legend', explains what the element means (or encodes) in the regex syntax. The next two columns work hand in hand: the 'Example' column gives a valid regular expression that uses the element, and the 'Sample Match' column presents a text string that could be matched by the regular expression.
You can read the tables online, of course, but if you suffer from even the mildest case of online-ADD (attention deficit disorder), like most of us… Well then, I highly recommend you print them out. You'll be able to study them slowly, and to use them as a cheat sheet later, when you are reading the rest of the site or experimenting with your own regular expressions.
Enjoy!
If you overdose, make sure not to miss the next page, which comes back down to Earth and talks about some really cool stuff: The 1001 ways to use Regex.

Regex Accelerated Course and Cheat Sheet

For easy navigation, here are some jumping points to various sections of the page:
✽ Characters
✽ Quantifiers
✽ More Characters
✽ Logic
✽ More White-Space
✽ More Quantifiers

Regex Builder

✽ Character Classes
✽ Anchors and Boundaries
✽ POSIX Classes
✽ Inline Modifiers
✽ Lookarounds
✽ Character Class Operations
✽ Other Syntax
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Characters

Character	Legend	Example	Sample Match
d	Most engines: one digit from 0 to 9	file_dd	file_25
d	.NET, Python 3: one Unicode digit in any script	file_dd	file_9੩
w	Most engines: 'word character': ASCII letter, digit or underscore	w-www	A-b_1
w	.Python 3: 'word character': Unicode letter, ideogram, digit, or underscore	w-www	字-ま_۳
w	.NET: 'word character': Unicode letter, ideogram, digit, or connector	w-www	字-ま‿۳
s	Most engines: 'whitespace character': space, tab, newline, carriage return, vertical tab	asbsc	a b c
s	.NET, Python 3, JavaScript: 'whitespace character': any Unicode separator	asbsc	a b c
D	One character that is not a digit as defined by your engine's d	DDD	ABC
W	One character that is not a word character as defined by your engine's w	WWWWW	*-+=)
S	One character that is not a whitespace character as defined by your engine's s	SSSS	Yoyo

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Quantifiers

Quantifier	Legend	Example	Sample Match
+	One or more	Version w-w+	Version A-b1_1
{3}	Exactly three times	D{3}	ABC
{2,4}	Two to four times	d{2,4}	156
{3,}	Three or more times	w{3,}	regex_tutorial
*	Zero or more times	A*B*C*	AAACC
?	Once or none	plurals?	plural

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More Characters

Character	Legend	Example	Sample Match
.	Any character except line break	a.c	abc
.	Any character except line break	.*	whatever, man.
.	A period (special character: needs to be escaped by a )	a.c	a.c
	Escapes a special character	.*+? $^/	.*+? $^/
	Escapes a special character	[{()}]	[{()}]

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Logic

Logic	Legend	Example	Sample Match
|	Alternation / OR operand	22|33	33
( … )	Capturing group	A(nt|pple)	Apple (captures 'pple')
1	Contents of Group 1	r(w)g1x	regex
2	Contents of Group 2	(dd)+(dd)=2+1	12+65=65+12
(?: … )	Non-capturing group	A(?:nt|pple)	Apple

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More White-Space

Character	Legend	Example	Sample Match
t	Tab	Ttw{2}	T ab
r	Carriage return character	see below
n	Line feed character	see below
rn	Line separator on Windows	ABrnCD	AB CD
N	Perl, PCRE (C, PHP, R…): one character that is not a line break	N+	ABC
h	Perl, PCRE (C, PHP, R…), Java: one horizontal whitespace character: tab or Unicode space separator
H	One character that is not a horizontal whitespace
v	.NET, JavaScript, Python, Ruby: vertical tab
v	Perl, PCRE (C, PHP, R…), Java: one vertical whitespace character: line feed, carriage return, vertical tab, form feed, paragraph or line separator
V	Perl, PCRE (C, PHP, R…), Java: any character that is not a vertical whitespace
R	Perl, PCRE (C, PHP, R…), Java: one line break (carriage return + line feed pair, and all the characters matched by v)

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More Quantifiers

Quantifier	Legend	Example	Sample Match
+	The + (one or more) is 'greedy'	d+	12345
?	Makes quantifiers 'lazy'	d+?	1 in 12345
*	The * (zero or more) is 'greedy'	A*	AAA
?	Makes quantifiers 'lazy'	A*?	empty in AAA
{2,4}	Two to four times, 'greedy'	w{2,4}	abcd
?	Makes quantifiers 'lazy'	w{2,4}?	ab in abcd

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Character Classes

Character	Legend	Example	Sample Match
[ … ]	One of the characters in the brackets	[AEIOU]	One uppercase vowel
[ … ]	One of the characters in the brackets	T[ao]p	Tap or Top
-	Range indicator	[a-z]	One lowercase letter
[x-y]	One of the characters in the range from x to y	[A-Z]+	GREAT
[ … ]	One of the characters in the brackets	[AB1-5w-z]	One of either: A,B,1,2,3,4,5,w,x,y,z
[x-y]	One of the characters in the range from x to y	[ -~]+	Characters in the printable section of the ASCII table.
[^x]	One character that is not x	[^a-z]{3}	A1!
[^x-y]	One of the characters not in the range from x to y	[^ -~]+	Characters that are not in the printable section of the ASCII table.
[dD]	One character that is a digit or a non-digit	[dD]+	Any characters, inc- luding new lines, which the regular dot doesn't match
[x41]	Matches the character at hexadecimal position 41 in the ASCII table, i.e. A	[x41-x45]{3}	ABE

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Anchors and Boundaries

Anchor	Legend	Example	Sample Match
^	Start of string or start of line depending on multiline mode. (But when [^inside brackets], it means 'not')	^abc .*	abc (line start)
$	End of string or end of line depending on multiline mode. Many engine-dependent subtleties.	.*? the end$	this is the end
A	Beginning of string (all major engines except JS)	Aabc[dD]*	abc (string... ...start)
z	Very end of the string Not available in Python and JS	the endz	this is...n...the end
Z	End of string or (except Python) before final line break Not available in JS	the endZ	this is...n...the endn
G	Beginning of String or End of Previous Match .NET, Java, PCRE (C, PHP, R…), Perl, Ruby
b	Word boundary Most engines: position where one side only is an ASCII letter, digit or underscore	Bob.*bcatb	Bob ate the cat
b	Word boundary .NET, Java, Python 3, Ruby: position where one side only is a Unicode letter, digit or underscore	Bob.*bкошкаb	Bob ate the кошка
B	Not a word boundary	c.*BcatB.*	copycats

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POSIX Classes

Character	Legend	Example	Sample Match
[:alpha:]	PCRE (C, PHP, R…): ASCII letters A-Z and a-z	[8[:alpha:]]+	WellDone88
[:alpha:]	Ruby 2: Unicode letter or ideogram	[[:alpha:]d]+	кошка99
[:alnum:]	PCRE (C, PHP, R…): ASCII digits and letters A-Z and a-z	[[:alnum:]]{10}	ABCDE12345
[:alnum:]	Ruby 2: Unicode digit, letter or ideogram	[[:alnum:]]{10}	кошка90210
[:punct:]	PCRE (C, PHP, R…): ASCII punctuation mark	[[:punct:]]+	?!.,:;
[:punct:]	Ruby: Unicode punctuation mark	[[:punct:]]+	‽,:〽⁆

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Inline Modifiers

None of these are supported in JavaScript. In Ruby, beware of (?s) and (?m).

Modifier	Legend	Example	Sample Match
(?i)	Case-insensitive mode (except JavaScript)	(?i)Monday	monDAY
(?s)	DOTALL mode (except JS and Ruby). The dot (.) matches new line characters (rn). Also known as 'single-line mode' because the dot treats the entire input as a single line	(?s)From A.*to Z	From A to Z
(?m)	Multiline mode (except Ruby and JS) ^ and $ match at the beginning and end of every line	(?m)1rn^2$rn^3$	1 2 3
(?m)	In Ruby: the same as (?s) in other engines, i.e. DOTALL mode, i.e. dot matches line breaks	(?m)From A.*to Z	From A to Z
(?x)	Free-Spacing Mode mode (except JavaScript). Also known as comment mode or whitespace mode	(?x) # this is a # comment abc # write on multiple # lines [ ]d # spaces must be # in brackets	abc d
(?n)	.NET, PCRE 10.30+: named capture only	Turns all (parentheses) into non-capture groups. To capture, use named groups.
(?d)	Java: Unix linebreaks only	The dot and the ^ and $ anchors are only affected by n
(?^)	PCRE 10.32+: unset modifiers	Unsets ismnx modifiers

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Lookarounds

Lookaround	Legend	Example	Sample Match
(?=…)	Positive lookahead	(?=d{10})d{5}	01234 in 0123456789
(?<=…)	Positive lookbehind	(?<=d)cat	cat in 1cat
(?!…)	Negative lookahead	(?!theatre)thew+	theme
(?<!…)	Negative lookbehind	w{3}(?<!mon)ster	Munster

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Character Class Operations

Class Operation	Legend	Example	Sample Match
[…-[…]]	.NET: character class subtraction. One character that is in those on the left, but not in the subtracted class.	[a-z-[aeiou]]	Any lowercase consonant
[…-[…]]	.NET: character class subtraction.	[p{IsArabic}-[D]]	An Arabic character that is not a non-digit, i.e., an Arabic digit
[…&&[…]]	Java, Ruby 2+: character class intersection. One character that is both in those on the left and in the && class.	[S&&[D]]	An non-whitespace character that is a non-digit.
[…&&[…]]	Java, Ruby 2+: character class intersection.	[S&&[D]&&[^a-zA-Z]]	An non-whitespace character that a non-digit and not a letter.
[…&&[^…]]	Java, Ruby 2+: character class subtraction is obtained by intersecting a class with a negated class	[a-z&&[^aeiou]]	An English lowercase letter that is not a vowel.
[…&&[^…]]	Java, Ruby 2+: character class subtraction	[p{InArabic}&&[^p{L}p{N}]]	An Arabic character that is not a letter or a number

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Other Syntax

Syntax	Legend	Example	Sample Match
K	Keep Out Perl, PCRE (C, PHP, R…), Python's alternate regex engine, Ruby 2+: drop everything that was matched so far from the overall match to be returned	prefixKd+	12
Q…E	Perl, PCRE (C, PHP, R…), Java: treat anything between the delimiters as a literal string. Useful to escape metacharacters.	Q(C++ ?)E	(C++ ?)

The 1001 ways to use Regex

Regex Python Cheat Sheet Printable

Regex Python Cheat Sheet Pdf

Regex Python Cheat Sheet Examples

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