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

@
@
imxg

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 = "(?imx)\n" + "(^\\h*) # capture les espaces avant #cs (ex. < >#cs)\n" + "(\n" + " \\# (?> cs|comments-start ) \\b\\N*\\R # => #cs\n\n" + " # => commentaires (partie entre #cs et #ce)\n" + " (?:\n" + " # vérifie qu'il s'agit bien d'un commentaire\n" + " # c.-à-d. que le début de la ligne NE doit PAS être suivi par ce qui\n" + " # correspond à un début (#cs) ou fin de commentaire (#ce)\n" + " (?!\n" + " \\h* \\# (?> cs|comments-start|ce|comments-end ) \\b\\N*\\R\n" + " )\n" + " # le commentaire\n" + " # un commentaire peut simplement être une nouvelle ligne (\\R)\n" + " \\N*\\R\n" + " | # commentaire ou récursion (si aucun commentaire trouvé)\n" + " # récursion (depuis le début) pour chercher un nouveau #cs\n" + " (?R)\n" + " )* # les commentaire sont facultatifs\n\n" + " \\h* \\# (?> ce|comments-end ) # => #ce\n\n" + " \\b\\N*? # texte après #ce, facultatif (ex. #ce< TEXTE>)\n" + ")\n\n" + "# capture, s'il y en a, les espaces et la fin de ligne après #ce (ex. #ce blabla...< \\R>)\n" + "(\n" + " \\h*+ $ # espaces après #ce ; seulement ceux avant la fin de ligne (ex. #ce blabla...< >$)\n" + " \\R? # retour à la ligne facultatif\n" + ")"; final String string = " #cs xyz\n" + " gna\n" + " #cs xyz\n" + " gna gna\n" + " #ce #ce\n" + " #ce #ce \n" + "#ce\n\n" + "#cs xyz\n" + " gna gna\n" + "#ce xyz\n\n" + "-------------------------------------\n\n" + "#cs\n" + " ...\n" + "#\n" + "#cs\n" + "#cs\n" + "#cs\n" + " ...\n" + "#cs\n" + " ...\n" + "#ce\n" + " #ce\n" + "#ce\n" + "#ce\n" + ";#ce\n" + "#ce\n" + "#ce\n" + "-------------------------------------\n" + "#comments-start BON\n" + " ...\n" + "#\n" + " #cs\n" + " ...\n" + " #cs\n" + " ...\n" + " #ce\n" + "#ce\n" + "...\n" + "#ce\n" + "-------------------------------------\n" + "#comments-start BON\n" + " ...\n" + "#\n" + " #comments-start\n" + " ...\n" + " #cs\n" + " ...\n" + "#comments-end\n" + " #ce\n" + "...\n" + "#comments-end \n" + "#comments-end\n" + "-------------------------------------\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce u u u u \n\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce u u u u\n\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce u u u u \n\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce \n\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce i\n\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce i\n\n" + " #cs\n" + ";#cs\n" + ";#ce\n" + "#ce i \n\n" + "-------------------------------------\n\n" + "#cs,test\n" + " ...\n" + "#cs...\n" + " .#cs.. NE_PAS_CAPTURER\n" + "#ceNE_PAS_CAPTURER\n" + " ...\n" + "#ce\n" + "#ce\n" + "#ce\n\n" + "-------------------------------------\n\n" + "#cs\n" + "#ce\n\n" + "#comments-start\n" + " ...\n" + " #\n" + " #cs\n" + " #cs\n" + " ...\n" + " #cs---\n" + " ...\n" + "#\n" + " # ce NE_PAS_CAPTURER\n" + " #ce\n" + " #ce\n" + "#ce\n" + " #ce\n" + "#ce\n\n" + "...\n" + "-------------------------------------\n" + "--------- [NE PAS CAPTURER] ---------\n" + "#ce\n\n" + "#ce\n" + "#ce\n\n" + "#cs\n\n" + "#cs\n" + "#cs\n\n" + "#cs\n" + "#cs\n" + "#cs\n"; final String subst = "[\\1]<span class=\"S2\">\\2</span>[\\3]"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.COMMENTS); 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