Home » Python Regex » Python Regex Cheat Sheet

Python Regex Cheat Sheet

This page provides a Python regex cheat sheet that you can quickly reference while working with regular expressions.

Character sets

Pattern	Meaning
`\w`	Match a single word character a-z, A-Z, 0-9, and underscore (_)
`\d`	Match a single digit 0-9
`\s`	Match whitespace including \t, \n, and \r and space character
`.`	Match any character except the newline
`\W`	Match a character except for a word character
`\D`	Match a character except for a digit
`\S`	Match a single character except for a whitespace character

Anchors

Pattern	Meaning
`^`	Match at the beginning of a string
`$`	Match at the end of a string
`\b`	Match a position defined as a word boundary
`\B`	Match a position that is not a word boundary

Quantifiers

Quantifiers (Greedy)	Non-greedy Quantifiers (Lazy)	Meaning
`*`	`*?`	Match its preceding element zero or more times.
`+`	`+?`	Match its preceding element one or more times.
`?`	`??`	Match its preceding element zero or one time.
`{n}`	`{n}?`	Match its preceding element exactly `n` times.
`{n , }`	`{n,}?`	Match its preceding element at least `n` times.
`{n , m}`	`{n , m}?`	Match its preceding element from `n` to `m` times

Sets & Ranges

Pattern	Meaning
`[XYZ]`	Match any of three elements X, Y, and Z
`[X-Y]`	Match a range from X to Y
`^[XYZ]`	Match any single element except X, Y, and Z
`^[X-Y]`	Match any single element
`{n , }`	Match its preceding element at least `n` times.
`{n , m}`	Match its preceding element from `n` to `m` times

Capturing Groups

Pattern	Meaning
`(X)`	Capture the X in the group
`(?P<name>X)`	Capture the X and assign it the name
`\N`	Reference the capturing group #N
`\g<N>`	Reference the capturing group #N (alternative syntax)

Alternation

Pattern	Meaning
`X \| Y`	Match either X or Y

Look Around

Pattern	Meaning
`X(?=Y)`	Match X but only if it is followed by Y
`X(?!Y)`	Match X but only if it is NOT followed by Y
`(?<=Y)X`	Match X if there is Y before it
`(?<!Y)X`	Match X if there is NO Y before it

Regex functions

The following table shows the regex function from the re module.

Function	Description
`findall()`	Return a list of matches or None
`finditer()`	Return an iterator yielding all non-overlapping matches
`search()`	Return the first match
`fullmatch()`	Return a Match object if the whole string matches a pattern
`match()`	Return the match at the beginning of a string or None
`sub()`	Return a string with matched replaced with a replacement
`split()`	Split a string at the occurrences of matches

Regex Flags

Flag	Alias	Inline Flag	Meaning
`re.ASCII`	`re.A`	`?m`	The `re.ASCII` is relevant to the byte patterns only. It makes the `\w`, `\W`,`\b`, `\B`, `\d`, \D, and `\S` perform ASCII-only matching instead of full Unicode matching.
`re.DEBUG`	N/A	N/A	The `re.DEBUG` shows the debug information of compiled pattern.
`re.IGNORECASE`	`re.I`	`?i`	perform case-insensitive matching. It means that the `[A-Z]` will also match lowercase letters.
`re.LOCALE`	`re.L`	`?L`	The `re.LOCALE` is relevant only to the byte pattern. It makes the `\w`, `\W`, `\b`, `\B` and case-sensitive matching dependent on the current locale. The `re.LOCALE` is not compatible with the `re.ASCII` flag.
`re.MUTILINE`	`re.M`	`?m`	The `re.MULTILINE` makes the `^` matches at the beginning of a string and at the beginning of each line and `$` matches at the end of a string and at the end of each line.
`re.DOTALL`	`re.S`	`?s`	By default, the dot (`.`) matches any characters except a newline. The `re.DOTALL` makes the dot (`.`) matches all characters including a newline.
`re.VERBOSE`	`re.X`	`?x`	The `re.VERBOSE` flag allows you to organize a pattern into logical sections visually and add comments.

Did you find this tutorial helpful ?

Python Regex Flags

Tkinter Tutorial