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Regular Expression has such power that it has been incorporated in many programming languages like Python, Pearl, JavaScript, PHP, and Java. So, let’s come back to our problem! We can get the users’ phone numbers by first creating a pattern. Python 3 Regular Expressions Cheat Sheet Teacher Mihai Catalin Teodosiu Categories E-book Review (0 review) Free Buy this course Overview Having a comprehensive cheat sheet at hand when working with regular expression patterns and syntax makes you more confident in. This cheat sheet is based on Python 3’s documentation on regular expressions. If you’re interested in learning Python, we have a free Python Programming: Beginner course for you to try out. Download the cheat sheet here. Special Characters ^ Matches the expression to its right at the start of a string. It matches every such instance. Python Python Regex Cheatsheet. Regular Expression Basics. Any character except newline: a: The character a: ab: The string ab: a b: a or b: a. Regular Expression Flags; i: Ignore case: m ^ and $ match start and end of line: s. Java programming language download for mac. Matches newline as well: x: Allow. Download simcity for mac for free. Having a comprehensive cheat sheet at hand when working with regular expression patterns and syntax makes you more confident in your skills and saves time. Mihai’s beginner-friendly teaching methods turned out to be very efficient for tens of thousands of students enrolled in his Python 2.x and 3.x video courses, published on various e.

Special characters

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

Regex Sheet Cheat

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()

Regex Cheat Sheet Pdf

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]]

Python Regular Expression Cheat Sheet With Examples

)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