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

@"
"
gmx

Test String

Substitution

Processing...

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = " \n" + " \n" + " (?<firstcapture> ~Start [^~]* ) #_(3) \n" + " (?<randomStuff> .*? ) #_(4) \n" + " \n" + " (?<loop_first> #_(5 start) \n" + " (?:\n" + " ~\n" + " (?: LOOP )\n" + " \\d [^~] \n" + " )\n" + " ( .*? ) # (1)\n" + " ) #_(5 end) \n" + " \n" + " (?:\n" + " (?<loop_middle> #_(6 start) \n" + " (?:\n" + " (?:\n" + " ~\n" + " (?: LOOP )\n" + " \\d [^~] \n" + " )\n" + " .*? \n" + " )*\n" + " ) #_(6 end) \n" + " (?<loop_last> #_(7 start) \n" + " (?:\n" + " ~\n" + " (?: LOOP )\n" + " \\d [^~] \n" + " )\n" + " ( .*? ) # (2)\n" + " ) #_(7 end) \n" + " )?\n" + " \n" + " (?<end> ~End [ ] stuff~ ) #_(8) \n"; final String string = " BlahBlahBlah~Start capture~Yadda~Yadda~Yadda~LOOP1 hello1~LOOP2 hello2~LOOP3 hello3~End stuff~\n\n" + " BlahBlahBlah~Start capture~Yadda~Yadda~Yadda~LOOP1 hello1~LOOP2 hello2~End stuff~\n\n" + " BlahBlahBlah~Start capture~Yadda~Yadda~Yadda~LOOP1 hello1~LOOP3 hello3~End stuff~\n\n" + " BlahBlahBlah~Start capture~Yadda~Yadda~Yadda~LOOP1 hello1~End stuff~\n"; final String subst = "${firstcapture}${randomStuff}${loop_last}${loop_middle}${loop_first}${end}"; final Pattern pattern = Pattern.compile(regex, 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