Regular Expressions 101

Save & Manage Regex

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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
Processing...

Test String

Substitution
Processing...

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 = "^([0-9.]+)\\s(.)\\s(.)\\s\\[(.*)\\s(\\+[0-9]*)\\]\\s\\\"GET|POST\\\""; final String string = "127.0.0.1 - - [11/Sep/2015:08:15:33 +0600] \"GET / HTTP/1.1\" 200 4189\n" + "127.0.0.1 - - [11/Sep/2015:08:15:33 +0600] \"GET /icons/blank.gif HTTP/1.1\" 200 148\n" + "127.0.0.1 - - [11/Sep/2015:08:15:33 +0600] \"GET /icons/folder.gif HTTP/1.1\" 200 225\n" + "127.0.0.1 - - [11/Sep/2015:08:15:33 +0600] \"GET /icons/text.gif HTTP/1.1\" 200 229\n" + "127.0.0.1 - - [11/Sep/2015:08:15:33 +0600] \"GET /icons/unknown.gif HTTP/1.1\" 200 245\n" + "127.0.0.1 - - [11/Sep/2015:08:15:33 +0600] \"GET /favicon.ico HTTP/1.1\" 404 1207\n" + "127.0.0.1 - - [11/Sep/2015:08:15:40 +0600] \"GET /public/ HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [11/Sep/2015:08:15:37 +0600] \"GET /public/ HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [08/Dec/2015:11:22:28 +0600] \"GET /public/index.php HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [08/Dec/2015:11:22:31 +0600] \"GET /favicon.ico HTTP/1.1\" 404 1239\n" + "127.0.0.1 - - [08/Dec/2015:11:22:34 +0600] \"GET / HTTP/1.1\" 200 4189\n" + "127.0.0.1 - - [08/Dec/2015:11:22:34 +0600] \"GET /icons/blank.gif HTTP/1.1\" 200 148\n" + "127.0.0.1 - - [08/Dec/2015:11:22:34 +0600] \"GET /icons/folder.gif HTTP/1.1\" 200 225\n" + "127.0.0.1 - - [08/Dec/2015:11:22:34 +0600] \"GET /icons/unknown.gif HTTP/1.1\" 200 245\n" + "127.0.0.1 - - [08/Dec/2015:11:22:34 +0600] \"GET /icons/text.gif HTTP/1.1\" 200 229\n" + "127.0.0.1 - - [08/Dec/2015:11:22:52 +0600] \"GET / HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [08/Dec/2015:11:23:05 +0600] \"GET / HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [08/Dec/2015:11:23:07 +0600] \"GET /public/index.php HTTP/1.1\" 404 16638\n" + "127.0.0.1 - - [08/Dec/2015:11:23:12 +0600] \"GET / HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [08/Dec/2015:11:23:40 +0600] \"GET /auth/ HTTP/1.1\" 301 332\n" + "127.0.0.1 - - [08/Dec/2015:11:23:40 +0600] \"GET /auth HTTP/1.1\" 404 16638\n" + "127.0.0.1 - - [08/Dec/2015:11:23:45 +0600] \"GET /auth/login HTTP/1.1\" 404 16638\n" + "127.0.0.1 - - [08/Dec/2015:11:23:49 +0600] \"GET / HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [08/Dec/2015:11:44:02 +0600] \"GET / HTTP/1.1\" 200 1046\n" + "127.0.0.1 - - [08/Dec/2015:12:11:53 +0600] \"GET / HTTP/1.1\" 200 1023\n" + "127.0.0.1 - - [29/Dec/2015:10:29:46 +0600] \"GET / HTTP/1.1\" 200 11160\n" + "127.0.0.1 - - [29/Dec/2015:10:29:47 +0600] \"GET /_debugbar/assets/stylesheets?1451362463 HTTP/1.1\" 200 196851\n" + "127.0.0.1 - - [29/Dec/2015:10:29:47 +0600] \"GET /_debugbar/assets/javascript?1451362459 HTTP/1.1\" 200 348784\n" + "127.0.0.1 - - [29/Dec/2015:10:29:48 +0600] \"GET /favicon.ico HTTP/1.1\" 200 -\n" + "127.0.0.1 - - [29/Dec/2015:10:30:58 +0600] \"GET /auth HTTP/1.1\" 404 29966\n" + "127.0.0.1 - - [29/Dec/2015:10:32:24 +0600] \"GET /_debugbar/open?max=20&offset=0 HTTP/1.1\" 200 289\n" + "127.0.0.1 - - [29/Dec/2015:11:08:46 +0600] \"GET /auth/register HTTP/1.1\" 404 28750\n" + "127.0.0.1 - - [30/Dec/2015:08:43:01 +0600] \"GET /auth/register HTTP/1.1\" 404 27092\n" + "127.0.0.1 - - [30/Dec/2015:08:43:14 +0600] \"GET /_debugbar/assets/stylesheets?1451362463 HTTP/1.1\" 200 196851\n" + "127.0.0.1 - - [30/Dec/2015:08:43:14 +0600] \"GET /_debugbar/assets/javascript?1451362459 HTTP/1.1\" 200 348784\n" + "127.0.0.1 - - [30/Dec/2015:08:43:15 +0600] \"GET /favicon.ico HTTP/1.1\" 200 -\n" + "127.0.0.1 - - [30/Dec/2015:11:51:32 +0600] \"GET / HTTP/1.1\" 200 9902\n" + "127.0.0.1 - - [30/Dec/2015:11:51:34 +0600] \"GET /favicon.ico HTTP/1.1\" 200 -\n" + "127.0.0.1 - - [30/Dec/2015:12:22:13 +0600] \"GET /auth HTTP/1.1\" 404 28622\n" + "127.0.0.1 - - [28/Mar/2016:12:32:18 +0600] \"GET / HTTP/1.1\" 200 9881\n" + "127.0.0.1 - - [28/Mar/2016:12:32:38 +0600] \"GET /_debugbar/assets/stylesheets?1451362463 HTTP/1.1\" 200 196851\n" + "127.0.0.1 - - [28/Mar/2016:12:32:38 +0600] \"GET /_debugbar/assets/javascript?1451362459 HTTP/1.1\" 200 348784\n" + "127.0.0.1 - - [28/Mar/2016:12:32:39 +0600] \"GET /favicon.ico HTTP/1.1\" 200 -\n"; final String subst = ""; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.CASE_INSENSITIVE); final Matcher matcher = pattern.matcher(string); // The substituted value will be contained in the result variable final String result = matcher.replaceAll(subst); System.out.println("Substitution result: " + result); } }

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