Regular Expressions 101

Save & Manage Regex

  • Current Version: 5
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
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]
  • Character class intersection
    [\w&&[^\d]]
  • 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
Processing...

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 = "((?:(\\w{1}|\\d).+([\\.?\\!\\)\\s]|\\b)?)+)|\\s?([\\w ]+[\\.\\?!] )"; final String string = "What about... this sentence?\n\n" + "Here's a list of things:\n\n" + "* one,\n" + " continued\n" + " - two.\n" + "* three,\n" + " - four\n" + " - five\n\n" + "1. Numbered one,\n" + " continued\n" + "2. numbered two.\n" + "3. numbered three.\n\n" + "every sentence starts with a capital. let's have that rule. but\n" + "what is a sentence?\n\n" + "42 is the answer.\n\n" + "I got a memory leak of the whole client-chat direcrive. sdf\n\n" + "this is a sentence\n" + "that continues down here. while this is a different sentence. (can we find sentences in brackets?)\n\n" + "Sentences sometimes (but not always), contain bracketed sections, e.g. as in this sentence; ok?\n\n" + "a sentence with no final punctuation should end if double-spaced\n\n\n" + " authorize.net Node.js filename-ish words & such don't terminate a sentence\n\n" + "I want to move my website from example.net to example.com blah blah blah.\n\n" + "I want to move my website from example.net to example.com blah blah blah\n\n" + "I want to move my website from example.net to _xCodexBlockxPlacexHolderx_\n" + " example.com blah blah blah.\n\n" + "_xCodexBlockxPlacexHolderx_\n\n" + "More than a 10% with 1.5 to 2 global load, etc.) to 1st level Flume collectors.\n\n" + "I am using AngularJS 1.3.0, but even after upgrade to 1.4.9 it still happens. (That should be just ONE sentence.)\n\n" + "A simple sentence, ending with punctuation.\n" + "A sentence without end punctuatione, ending with double-space\n\n" + "\"A sentence in quotes.\" \"Ok with that?\" \"punctuation after the close quote\"!\n" + "###This is a heading\n\n" + "Text in a link [is part of the sentence][1].\n\n" + "Another sentence. And another sentence? End of file!"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | 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