Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
g

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"\?st=\K\S+(?=\s*target|$)" test_str = "<TABLE cellPadding=3 width=100%><td><font class=btime>20:53</font>&nbsp;&nbsp;<a href=news2.php?st=1414691580 target=right>Кыргызстан: понастроили мечетей.., - Омор Рысбаев</a><br><font class=btime>20:50</font>&nbsp;&nbsp;<a href=news2.php?st=1414691400 target=right>Исламская Изида: как джихадисты вынуждают западные компании менять названия</a><br><font class=btime>20:48</font>&nbsp;&nbsp;<a href=news2.php?st=1414691280 target=right>Не прошло и двух лет. Российский летчик Петренко освобожден из плена талибов в Афганистане</a><br><font class=btime>19:58</font>&nbsp;&nbsp;<a href=news2.php?st=1414688280 target=right>Игорь Стрелков объявил о создании общественного движения \"Новороссия\"</a><br><font class=btime>19:27</font>&nbsp;&nbsp;<a href=news2.php?st=1414686420 target=right>Давление США на Россию будет только нарастать. Зачем Путин дал слабину? - Гао Фэн</a><br><font class=btime>19:21</font>&nbsp;&nbsp;<a href=news2.php?st=1414686060 target=right>Путин не знает страны, в которой живет. Тайга давным-давно полыхает.., - Э.Ханымамедов</a><br><font class=btime>19:11</font>&nbsp;&nbsp;<a href=news2.php?st=1414685460 target=right>Протестующие в Буркина-Фасо подожгли парламент, пытаясь свернуть бессменного (с 1987) президента Блэза Компаоре</a><br><font class=btime>18:37</font>&nbsp;&nbsp;<a href=news2.php?st=1414683420" matches = re.finditer(regex, test_str) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html