Regular Expressions 101

Save & Share

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

/
/
gmi

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"(((\w\d+|\w+)(\W+)?)?(\s+)?(U;)?(\s+)?(CrOS|Cross|CrossOS))(\s+)(x86_64|x8664|x86_x64|armv\d+|aarch\d+|i\d+|amd64)" test_str = (" 331 Mozilla/5.0 (X11; U; CrOS i686 0.9.128; ru) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.343 Safari/534.10\n" " 638 Mozilla/5.0 (X11; U; CrOS i686 0.9.128; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.343 Safari/534.10\n" " 661 Mozilla/5.0 (X11; U; CrOS i686 0.9.128; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.341 Safari/534.10\n" " 667 Mozilla/5.0 (X11; U; CrOS i686 0.13.507) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36\n" " 744 Mozilla/5.0 (X11; U; CrOS i686 0.13.507) AppleWebKit/600.7.12 (KHTML, like Gecko) Version/8.0.7 Safari/600.7.12\n" " 903 Mozilla/5.0 (X11; U; CrOS i686 9.10.0; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.0.253.0 Safari/532.5\n" " 949 Mozilla/5.0 (x11; Cross x86_64 12739.105.0) Applewebkit/537.36 (KHTML, like gecko)Chrome/80.0.3987.158 Safari/537.36\n" " 1147 Mozilla/5.0 (Wizyconf CrOS x86_64 11021.111.2020 9c7514400ffe) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.124 Safari/537.36\n" " 1200 Mozilla/5.0 (X11; CrOS x8664 6680.78.0) AppleWebKit/537.36 (KHTML like Gecko) Chrome/41.0.2272.102 Safari/537.36\n" " 1376 Mozilla/5.0 (X11; CrOS x8664 5978.98.1) AppleWebKit/537.36 (KHTML like Gecko) Chrome/37.0.2062.120 Safari/537.36\n" " 1513 Mozilla/5.0 (X11; U; CrOS i686 0.13.507) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/14.0.835.94 Safari/535.1\n" " 1560 Mozilla/5.0 (X11;CrOS aarch64 13099.85.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.4147.110 Safari/537.36\n" " 1917 Mozilla/5.0 (X11CrOS i686 2268.111.0) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.57 Safari/536.11\n" " 1935 Mozilla/5.0 (X11; CrOS x8664 5978.80.0) AppleWebKit/537.36 (KHTML like Gecko) Chrome/37.0.2062.119 Safari/537.36\n" " 2036 Mozilla/5.0 (X11; CrOS x86_x64 8787.87.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.8787.87 Safari/537.36\n" " 2140 Mozilla/5.0 (Wizyconf CrOS x86_64 11021.111.2020 9c7514400083) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.124 Safari/537.36\n" " 2289 Mozilla/5.0 (Wizyconf CrOS x86_64 11021.111.2021 9c7514400083) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.124 Safari/537.36\n" " 2716 Mozilla/5.0 (Linxus; Android 11; CrOS x86_64 13904.97.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Mobile Safari/537.36\n" " 2790 Mozilla/5.0 (Wizyconf CrOS x86_64 13904.98.2021 9c7514400083) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.167 Safari/537.36\n" " 2851 Mozilla/5.0 (Wizyconf CrOS x86_64 13904.98.2021 ) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.167 Safari/537.36\n" " 2989 Mozilla/5.0 (Wizyconf CrOS x86_64 11021.111.2019 9c7514400511) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.124 Safari/537.36\n" " 3037 Mozilla/5.0 (X11; Windows x86_64 13904.97.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.167 Safari/537.36 CitrixChromeApp\n" " 3107 Mozilla/5.0 (Android <Android Version>; Microsoft) AppleWebKit/<WebKit Rev> (KHTML, like Gecko) Chrome/62.0.3202.66 Mobile Safari/534.30 Edge/<EdgeHTML Rev>\n" " 3212 Mozilla/5.0 (X11; CROSSOS amd64) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0 Safari/605.1.15\n" " 3303 Mozilla/5.0 (Wayland; CrOS x86_64;POV_TV-HDMI-200BT Build/JRO03H14268.67.0) AppleWebKit/605.1.15 (KHTML, like Gecko) Chrome/100.0.3770.100 Safari/605.1.15\n" " 3304 Mozilla/5.0 (Wayland; CrOS x86_64 14268.67.0) AppleWebKit/605.1.15 (KHTML, like Gecko) Chrome/100.0.3770.100 Safari/605.1.15\n" " 3379 Mozilla/5.0 (X11; Windows x86_64 14388.52.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.91 Safari/537.36 CitrixChromeApp\n" " 4395 Mozilla/5.0 (X11;CrOS armv7i 13982.88.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36 [ip:79.25.95.226]\n" " 4396 Mozilla/5.0 (X11;CrOS armv7i 13982.88.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 14150.7.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.12 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS i686 7077.123.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.155 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 13748.0.2021) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4395.3 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS aarch64 14150.3.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.5 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 13982.82.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.157 Safari/537.36,gzip(gfe)\n" "Mozilla/5.0 (X11; CrOS aarch64 13982.75.2021) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.138 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS aarch64 14150.7.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.12 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 13816.93.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.230 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 13794.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4418.0 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS aarch64 13505.100.3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.142 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 14092.32.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.46 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 12499.38.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.69 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 13982.84.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36\n" "Mozilla/5.0 (X11; CrOS x86_64 14092.35.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.16 Safari/537.36\n") matches = re.finditer(regex, test_str, re.MULTILINE | re.IGNORECASE) 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