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

/
/
g

Test String

Code Generator

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"(\s+)(\S+)=[\"']?((?:.(?![\"']?\s+(?:\S+)=|[>\"']))+.)[\"']?" test_str = ("<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">On Friday, November 13, 2015, at approximately 3:24 p.m., the Sacramento Police Department responded to the intersection of Mabel Street and Silver Eagle Road regarding the report of a shooting.</span><span style=\"font-size: small;\"><span style=\"mso-spacerun: yes;\">&nbsp;&nbsp; </span></span></span></p>\n" "<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">Officers received additional information that the victim&rsquo;s vehicle, occupied by five juveniles, was driving east-bound on Silver Eagle Road when it stopped at the intersection of Mabel Street.</span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp;&nbsp; </span></span><span style=\"font-size: small;\">At that time, the unknown suspect(s) fired multiple rounds at the vehicle, striking the driver and the front passenger. </span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp;</span></span><span style=\"font-size: small;\">The suspect(s) fled the scene in an unknown direction of travel.</span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp; </span></span><span style=\"font-size: small;\">It is unknown at this time if the suspect(s) were in a vehicle or on foot at the time of the assault.</span><span style=\"font-size: small;\"><span style=\"mso-spacerun: yes;\">&nbsp; </span></span></span></p>\n" "<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">After the shooting, all of the passengers exited the vehicle.</span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp; </span></span><span style=\"font-size: small;\">One of the passengers put the critically-injured driver in the back seat of the car and drove him to the 1400 block of Grand Avenue.</span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp; </span></span><span style=\"font-size: small;\">Sacramento Fire Department personnel responded and transported the 17-year-old juvenile to an area hospital where he later succumbed to his injuries. </span></span></p>\n" "<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">The remaining juveniles hailed an uninvolved, passerby who transported the front passenger to an area hospital where he is being treated for a non-life threatening injury.</span><span style=\"font-size: small;\"><span style=\"mso-spacerun: yes;\">&nbsp; </span></span></span></p>\n" "<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">Homicide detectives along with Crime Scene Investigators were summoned to the crime scene to begin collecting evidence, and canvassing the area. </span></span></p>\n" "<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">A specific motive has not been determined in this incident.</span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp; </span></span><span style=\"font-size: small;\">The investigation remains very active and no arrests have been made.</span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp; </span></span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp;&nbsp;&nbsp;</span></span><span style=\"mso-spacerun: yes;\"><span style=\"font-size: small;\">&nbsp;&nbsp;</span></span><span style=\"font-size: small;\"><span style=\"mso-spacerun: yes;\">&nbsp;</span></span></span></p>\n" "<p class=\"MsoNormal\" style=\"margin: 0in 0in 10pt;\"><span style=\"font-family: &quot;Gill Sans MT&quot;,&quot;sans-serif&quot;; mso-bidi-font-family: Arial;\"><span style=\"font-size: small;\">Sacramento Police Department detectives encourage any witnesses with information to contact the dispatch center at (916) 264-5471 or Crime Alert at (916) 443-HELP (4357) or text in a tip to 274637 (CRIMES). Enter SACTIP followed by the tip information. Callers can remain anonymous and may be eligible for a reward of up to $1,000.</span></span></p>") 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