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 = "(?:(?:\\d[- _]*){6,})|(?<num_1>\\d[- _]*)(?<num_2>\\d[- _]*)(?<num_3>\\d[- _]*)(?<num_4>\\d)(?<num_5>[- _]*\\d)?"; final String string = "\"1-2-3-4-5-6\" => no\n" + "\"1-2-3-4-5\" => yes match 1\n" + "\"1-2-3-4\" => yes match 2\n" + "\"1-2-3\" => no\n" + "\"123456\" => no\n" + "\"12345\" => yes match 3\n" + "\"1234\" => yes match 4\n" + "\"123\" => no\n" + "foo 123 56 78 bar\n" + "\"0000\" will become \"****\"\n" + "\"any text 000 00 more texts\" will become \"any text ***** more texts\"..notice that the space is removed\n" + "\"any text 000 00 more texts 00\" will become \"any text ***** more texts 00\"\n\n" + "\"any text 000 00 more texts 00 00\" will become \"any text ***** more texts ****\"\n\n" + "\"any text 00-00 more texts 00_00\" will become \"any text **** more texts ****\"\n" + "a 0 12345 fdf"; 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