Regular Expression Cheat Sheet for Dummies

Regex Basics	Description
^	The start of a string
$	The end of a string
.	Wildcard which matches any character, except newline (n).
|	Matches a specific character or group of characters on either side (e.g. a|b corresponds to a or b)
	Used to escape a special character
a	The character “a”
ab	The string “ab”

Quantifiers	Description
*	Used to match 0 or more of the previous (e.g. xy*z could correspond to “xz”, “xyz”, “xyyz”, etc.
?	Matches 0 or 1 of the previous
+	Matches 1 or more of the previous
{5}	Matches exactly 5
{5, 10}	Matches everything between 5-10

Character Classes	Description
s	Matches a whitespace character
S	Matches a non-whitespace character
w	Matches a word character
W	Matches a non-word character
d	Matches one digit
D	Matches one non-digit
[b]	A backspace character
c	A control character

Special Characters	Description
n	Matches a newline
t	Matches a tab
r	Matches a carriage return
ZZZ	Matches octal character ZZZ
xZZ	Matches hex character ZZ
	A null character
v	A vertical tab

Groups	Description
(xyz)	Grouping of characters
(?:xyz)	Non-capturing group of characters
[xyz]	Matches a range of characters (e.g. x or y or z)
[^xyz]	Matches a character other than x or y or z
[a-q]	Matches a character from within a specified range
[0-7]	Matches a digit from within a specified range

String Replacements	Description
$`	Insert before matched string
$’	Insert after matched string
$+	Insert last matched
$&	Insert entire match
$n	Insert nth captured group

Assertions	Description
(?=xyz)	Positive lookahead
(?!xyz)	Negative lookahead
?!= or ?<!	Negative lookbehind
b	Word Boundary (usually a position between /w and /W)
?#	Comment

Source

https://www.debuggex.com/cheatsheet/regex/python

https://www.keycdn.com/support/regex-cheatsheet

https://docs.python.org/3/library/re.html