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 = "^(?!.*(\\.com?\\.)|\\.com\\.).*$"; final String string = "regexp_repalce with negated character class:\n" + "yahoo\\.co[^\\.].*\n\n" + "https://stackoverflow.com/questions/977251/regular-expressions-and-negating-a-whole-character-group\n" + "^(?!.*ab).*$\n\n" + ".es\n\n" + "yahoo.es\n" + "yahoo.fr\n" + "yahoo.ca\n" + "yahoo.cm\n" + "yahoo.cn\n" + "yahoo.tw\n" + "yahoo.co.jp\n" + "yahoo.co.kr\n" + "yahoo.co.uk\n" + "yahoo.com.cn\n" + "yahoo.com.hk\n" + "yahoo.com.mx\n" + "yahoo.com.tw\n\n" + "REPLACE\n" + "yahoo.co\n" + "yahoo.co,\n" + "yahoo.com\n" + "yahoo.com,\n" + "yahoo.com.\n" + "yahoo.com'\n" + "yahoo.com/haltokariev\n" + "yahoo.com>\n" + "yahoo.com21yahoo.com\n" + "yahoo.comcom\n" + "yahoo.comheatdoc1123\n\n" + "yahoo\n" + "yahoomail.com keep\n" + "yahool.com\n" + "yahooo.com\n" + "yahoo.comj\n" + "yahoo.net\n" + "yahoocom\n\n\n" + "yahoo.com.hk\n" + "yahoo.co.uk\n" + "yahoo.es\n" + "yahoo.co\n" + "yahoo.com.tw\n" + "yahoo.fr\n" + "yahoo.ca\n\n" + "gmasucciarchitects.com\n" + "gmirealtyllc.com\n" + "gmarchitects.nett\n" + "gmarchitects.nte\n" + "gmachitects.net\n" + "gmarchitects.net\n\n\n" + "g-mail.com\n" + "g.mail.com\n" + "gailmail.com\n" + "gamail.com\n" + "gaol.com\n" + "geeemail.com\n" + "gemail.com\n" + "gfmail.com\n" + "ggmail.com\n" + "gimail.com\n" + "gmai.com\n" + "gmai9l.com\n" + "gmaiil.com\n" + "gmail\n" + "gmail.\n" + "gmail..com\n" + "gmail.c\n" + "gmail.cim\n" + "gmail.cm\n" + "gmail.co\n" + "gmail.com\n" + "gmail.com.\n" + "gmail.com.com\n" + "gmail.com101\n" + "gmail.com2014505140\n" + "gmail.com8206\n" + "gmail.comalexandrasceboldsecretary\n" + "gmail.comaol.com\n" + "gmail.combchan43460\n" + "gmail.comc\n" + "gmail.comceciliaschiera\n" + "gmail.comcolecole.cc1\n" + "gmail.comi\n" + "gmail.comil.com\n" + "gmail.comj\n" + "gmail.comjamesesber\n" + "gmail.coml.com\n" + "gmail.comleponto\n" + "gmail.comll\n" + "gmail.comlwilliams102\n" + "gmail.comm\n" + "gmail.comment.com\n" + "gmail.commipg820\n" + "gmail.comn\n" + "gmail.comnaka\n" + "gmail.comnr.aidan.collins\n" + "gmail.comol.com\n" + "gmail.comorapa0013\n" + "gmail.con\n" + "gmail.coom\n" + "gmail.cpm\n" + "gmail.cvom\n" + "gmail.gmail.com\n" + "gmail.net\n" + "gmail.om\n" + "gmail.oom\n" + "gmail.you\n" + "gmail1.com\n" + "gmail8203.com\n" + "gmailc.com\n" + "gmailc.om\n" + "gmailcom\n" + "gmailfurman.com\n" + "gmaill.com\n" + "gmaillcom\n" + "gmailmgmtcom\n" + "gmails.com\n" + "gmailus.com\n" + "gmaiol.com\n" + "gmal.com\n" + "gmale.com\n" + "gmall.com\n" + "gmaol.com\n" + "gmauil.com\n" + "gmial.com\n" + "gmil.com\n" + "gmila.com\n" + "gmmail.com"; 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