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
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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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

/
/
gm

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "^(?:ftp|https?):\\/\\/(?!0\\.0\\.0\\.0$)(?:(?:(?:1?\\d\\d?|2[0-4]\\d|25[0-5])(?:\\.(?!$))?){4}|(?:[a-zA-Z\\d]\\.|[a-zA-Z\\d](?:(?![-.]{2})[a-zA-Z\\d-]){0,63}?[a-zA-Z\\d]\\.){1,63}?[a-z]{2,63})(?:[:/].*)?$"; final String string = "---- GOOD ----\n" + "http://10.25.41.81:6000/api/File/GetContentResult?ObjectId=62ab059f5045ea0bb69e00d9\n" + "http://10.25.41.81:6600/api/File/GetContentResult?ObjectId=62ab0d9e5045ea0bb69e00e4\n" + "http://10.25.41.81:6600/api/File/GetContentResult?ObjectId=62a89a8c4f3326cc410c40ef\n" + "http://10.25.41.33:6600/api/File/GetContentResult?ObjectId=62ab04855045ea0bb69e00d7\n" + "https://websitebuilders.com\n" + "https://www.fceboo.k.com/Learn-the-Net-330002341216/\n" + "ftp://aeneas.m.it.edu/\n" + "https://en.wkip.ed-i.org/wiki/Internet#Terminolog\n" + "http://foo.com/blah_blah\n" + "http://foo.com/blah_blah/\n" + "http://foo.com/blah_blah_(wikipedia)\n" + "http://foo.com/blah_blah_(wikipedia)_(again)\n" + "http://www.example.com/wpstyle/?p=364\n" + "https://www.example.com/foo/?bar=baz&inga=42&quux\n" + "http://a.ws/䨹\n" + "http://foo.com/blah_(wikipedia)#cite-1\n" + "http://foo.com/blah_(wikipedia)_blah#cite-1\n" + "http://foo.com/unicode_(✪)_in_parens\n" + "http://foo.com/(something)?after=parens\n" + "http://code.google.com/events/#&product=browser\n" + "http://js.mp\n" + "ftp://foo.bar/baz\n" + "http://foo.bar/?q=Test%20URL-encoded%20stuff\n" + "http://1337.net\n" + "http://a.b-c.de\n" + "http://223.255.255.254\n" + "https://example.com/././foo\n" + "https://EXAMPLE.com/../x\n" + "https://example.org//\n" + "https://example.org/foo bar\n" + "http://foo.bar/foo(bar)baz quux\n" + "https://example.com:demo\n" + "https://r.com/r/zxVH\n\n" + "---- BAD ----\n" + "https://user:password@example.org/\n" + "http://userid:password@example.com:8080\n" + "http://userid:password@example.com:8080/\n" + "http://userid:password@example.com\n" + "http://userid:password@example.com/\n" + "http://userid@example.com\n" + "http://userid@example.com/\n" + "http://userid@example.com:8080\n" + "http://userid@example.com:8080/\n" + "file://loc%61lhost/\n" + "http://⌘.ws\n" + "http://⌘.ws/\n" + "http://☺.damowmow.com/\n" + "http://✪df.ws/123\n" + "http://[www.example.com]/\n" + "https://ex ample.org/\n" + "file://C|/demo\n" + "\\example\\..\\demo/.\\\n" + "https:example.org\n" + "https://////example.com///\n" + "http://0.0.0.0\n" + "http://3628126748\n" + "http://www.foo.bar./\n" + "http://a.b-.co\n" + "http://-a.b.co\n" + "http://-error-.invalid/\n" + "http://~_!$&'()*+,;=:%40:80%2f::::::@example.com\n" + "http://\n" + "http://.\n" + "http://..\n" + "http://../\n" + "http://?\n" + "http://??\n" + "http://??/\n" + "http://#\n" + "http://##\n" + "http://##/\n" + "http://foo.bar?q=Spaces should be encoded\n" + "//\n" + "//a\n" + "///a\n" + "///\n" + "http:///a\n" + "foo.com\n" + "rdar://1234\n" + "h://test\n" + "http:// shouldfail.com\n" + ":// should fail\n" + "ftps://foo.bar/\n" + "http://.www.foo.bar/\n" + "http://.www.foo.bar./\n"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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