Regular Expressions 101

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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
No Match

`
`
gm

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 = "^(([Rr]ef|[Cc]loses|[Rr]elated|[Ff]ixes|[Pp]artial)(:|) (#\\d+|\\w+\\#\\d+|(https://|)gitlab.com/volterra/.*/issues/\\d+))|noref$"; final String string = "ref #629\n" + "Ref #629\n" + "ref specification#629\n" + "Ref specification#629\n" + "ref https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Ref https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "ref gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Ref gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "ref: #629\n" + "Ref: #629\n" + "ref: specification#629\n" + "Ref: specification#629\n" + "ref: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Ref: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "ref: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Ref: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "closes #629\n" + "Closes #629\n" + "closes specification#629\n" + "Closes specification#629\n" + "closes https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Closes https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "closes gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Closes gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "closes: #629\n" + "Closes: #629\n" + "closes: specification#629\n" + "Closes: specification#629\n" + "closes: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Closes: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "closes: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Closes: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "related #629\n" + "Related #629\n" + "related specification#629\n" + "Related specification#629\n" + "related https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Related https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "related gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Related gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "related: #629\n" + "Related: #629\n" + "related: specification#629\n" + "Related: specification#629\n" + "related: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Related: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "related: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Related: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "fixes #629\n" + "Fixes #629\n" + "fixes specification#629\n" + "Fixes specification#629\n" + "fixes https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Fixes https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "fixes gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Fixes gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "fixes: #629\n" + "Fixes: #629\n" + "fixes: specification#629\n" + "Fixes: specification#629\n" + "fixes: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Fixes: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "fixes: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Fixes: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "partial #629\n" + "Partial #629\n" + "partial specification#629\n" + "Partial specification#629\n" + "partial https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Partial https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "partial gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Partial gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "partial: #629\n" + "Partial: #629\n" + "partial: specification#629\n" + "Partial: specification#629\n" + "partial: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Partial: https://gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "partial: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "Partial: gitlab.com/volterra/ves.io/specifications/-/issues/629\n" + "noref\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