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

/
/
g

Test String

Code Generator

Language

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "https?:\\/\\/(www.)?[a-zA-Z]+(\\.[a-zA-Z]+)+(\\/(\\w|[-_%.#?=&+])+)+"; final String string = "http://apne.ws/1nRjKS0\n" + "http://bit.ly/9H0CQT\n" + "http://twitter.com/BBCTimWillcox\n" + "http://www.bbc.co.uk/news/magazine-18529371\n" + "http://bbc.in/Mb1PWM\n" + "http://bbc.in/PCXSFT\n" + "http://nbcnews.to/ReH3pK \n" + "http://www.breakingnews.com/topic/75-earthquake-off-alaska-january-2013\n" + "http://online.wsj.com/news/articles/SB10001424052702304908304579568590603893\n" + "http://on.cnn.com/13DsWkq\n" + "http://cnnmon.ie/1GZiy8l \n" + "http://reut.rs/1sOV13M\n" + "http://on.fb.me/i1i3sT\n" + "http://econ.st/fcUlsA\n" + "http://on.wsj.com/SIji5s\n" + "http://on.wsj.com/1J4Id3r\n" + "https://word.office.live.com/wv/WordView.aspx?FBsrc=https%3A%2F%2Fwww.facebook.com%2Fattachments%2Ffile_preview.php%3Fid%3D713981818737203%26time%3D1453372782%26metadata&access_token=1604966176%3AAVKzw1ZzsEjWvtPbeu8TWvHPb3URXSaCRCdnoJsfz5TVnQ&title=2016+Stage+ILE+Simulation+d_un+syste_me+d_armes+sous+Simulink.doc\n" + "https://www.facebook.com/groups/522095331140491/?multi_permalinks=1255982751085075&ref=notif&notif_t=group_highlights"; final Pattern pattern = Pattern.compile(regex); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html