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

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 = "(\\w+\\s*\\n*=\\s*\\n*)\\{\\n*\\s*`((?:[^`](?!(?:\\$\\{|\\n|(?:'[^`]*\"|\"[^`]*'))))*)`\\n*\\s*\\}"; final String string = "// Match!\n" + "<Component1\n" + " // Using backticks without utilizing their functionalities\n" + " className={`flex justify-center items-center gap-2`}\n" + " description={``}\n" + " content={\n" + " `These backticks are unnecessary`\n" + " }\n" + " // This is a crime, but I did take it into account\n" + " horrendousFormatting\n" + " =\n" + " {`Please never do something like this`}\n" + "/>\n\n" + "// Multiple matches in a single line\n" + "<svg width={`100%`} height={`100%`} />\n\n" + "// Cases where this regex won't match:\n" + "<Component2\n" + " // Non-string property\n" + " disabled={isDisabled}\n" + " // Quotes/Single quotes with unnecessary brackets\n" + " // (I have another regex that's better adapted for this!)\n" + " href={\"https://regex101.com/library/l9MPcQ\"}\n" + " // String templating\n" + " className={`flex items-center justify-center size-5 ${iconColor}`}\n" + " // Escaping BOTH \" AND ' IN THE SAME STRING with backticks\n" + " title={`This string's backticks are \"justified\"`}\n" + " // Escaping line breaks with backticks\n" + " description={\n" + " `String with\n" + " a line break`\n" + " }\n" + " // \"/'/` mismatch\n" + " content={`Yeah this will turn the rest of your file into a string\"}\n" + ">\n" + " {icon}\n\n" + " // No match since this is not a property\n" + " {` `}\n\n" + " (Some people do this instead of using &nbsp;)\n" + "</Component2>\n"; final String subst = "$1\"$2\""; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); 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