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

/
/
g

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 = "(?<!\\\\)(?:\\[{2}[^\\n|]+(?:\\|[^\\n]+)?]]|\\[[^\\n]+]\\([^\\n:]+\\))"; final String string = "[[Link name|title]]\n\n" + "[[Link name]]\n\n" + "[[do not\n" + "|match]]\n" + "[I am not a link]]\n" + "some (text) [[Link]] more [text]\n\n" + "\\[[This is not a link]]\\[[[this is|a link]] foo bar ]\n\n" + "[[Folder Name/Link|link]]\n\n" + "[[Folder/other folder/file|label]]\n\n" + "[[]]\n" + "[[A [link] with brackets]]\n\n" + "[[A [link] with brackets|on [both] sides]]\n\n" + "[[A [bracket] folder/A [link] with brackets|on [both] sides]]\n\n" + "Markdown: [Three laws of motion](Three%20laws%20of%20motion.md)\n\n" + "\\[Not a link](Three%20laws%20of%20motion.md)\n\n" + "[also\n" + "not](a link)\n\n" + "[This [is] a link](Three%20laws%20of%20motion.md)\n\n" + "[Yes, you can put (parens) and [brackets] in a filename](Yes,%20you%20can%20put%20(parens)%20and%20[brackets]%20in%20a%20filename)\n\n" + "[This is an external link](https://regex101.com)\n\n" + " [[#Preview a linked file]] is a link to a heading in the current document.\n\n" + " [[Obsidian#Links are first-class citizens]] is a link to a heading in another document.\n\n" + "[[Help and support#Questions and advice#Report bugs and request features]] is a link to a subheading in another document.\n\n" + "You can link to a block by adding #^ at the end of your link destination followed by a unique block identifier. For example, [[2023-01-01#^37066d]]"; final Pattern pattern = Pattern.compile(regex); 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