Regular Expressions 101

Save & Share

  • Regex Version: ver. 18
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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 single character of: a, b, c or d
    [[ab][cd]]
  • 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
No Match

"
"
gi

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 = "(?<=\\\"access_token\\\" : ).*"; final String string = "{\n" + " \"access_token\": \"eyJraWQiOiJhZTYxYWIxZi0yNTRhLTQ5ZWQtODMzNC05ZDJlN2E0MzZiNGQuaG9tLmdlbi4xNTk3NjAwMzM2OTkyLmp3dCIsImFsZyI6IlJTMjU2In0.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.C29wuhkVvrR9KJ-g_BqziDUXcYIHL3vEsvNcHdJ9qCWceV8vWTbj9flt75SdkEmUkeOpxwKzZ9bt5ML680qtqhM5nOlQp7VMnJ3YM-f8myJI5db8ydkZ_2i0uy50I4VSy9091qjkoykD1LA9G_9SdCpKxunFRONxaZMeWbTs3phL9pHCuxai63PlHPGg8zYvYhOheK131epoAxyRS6-qCIY9OgqQWKg5fQxNu3xOKdTfyCvULPobSfVFNuwrUQWiVClju_qcoNTAyXl0T-sNuKKfqdVdm9AehMtXjNBGeG3a77AutLu2E-0PkQGxs9pM7D3pcbWhSiZJOZnAaV5bYw\",\n" + " \"refresh_token\": \"eyJraWQiOiJyZWZyZXNoLmhvbS5nZW4uaW50ZXJuYWwuand0IiwiYWxnIjoiUlMyNTYifQ.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.TiUf9yUj5Gnxf-p8iMVHoRVh3ssM6DBOvxsYdz-mMo3kM7cmiKoFz9LtholHrohC6BRxkQdSfWl-RXz4TyWuWTAsKEKTjfSw0NimhQ5fUq2D_OHFgFyVjxxuMOaU4aVBcyTT3bvhixkIB72_BYoSb0ACFmWhHDreg_B0hpTIzTJs4FPUGL2nMUFzdXMuXu080jXjeVvd2l5rMRJwNow91kclCTc2vRtziK5PuJJfiTI7QfLc_LiyesZpeH8pm7sMCpQY-G-xKzlZgrankneO2wnUbAd-hBq7MxERw_hR-49ZS_qzMKCtlEiT1hZqkCFpErf4ucCDIZ3c7jXijT_R-A\",\n" + " \"scope\": \"mf.CICS resource.READ mf.QT mf.IMS mf.GRBE appid-b1f5db31-6331-4098-a881-704a91008ac4\",\n" + " \"active\": true,\n" + " \"token_type\": \"Bearer\",\n" + " \"expires_in\": 300\n" + "}"; final String subst = "eyJhbGciOiJIUzI1NiJ9..73wb-VXApdLp1P2SEXCk7EWALdc3K0paOfjdbr4yZ4s"; final Pattern pattern = Pattern.compile(regex, 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