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

/
/
gix

Test String

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" + " (?<alpha>[a-z])\n" + " (?<digit>[0-9])\n" + " (?<unreserved>\\g<alpha>|\\g<digit>|-|\\.|_|~)\n" + " (?<hexdig>\\g<digit>|[A-F])\n" + " (?<pct_encoded>%\\g<hexdig>{2})\n" + " (?<gen_delims>[:\\/\\?\\#\\[\\]@])\n" + " (?<sub_delims>[!\\$&'\\(\\)\\*\\+,;=])\n" + " (?<reserved>\\g<gen_delims>|\\g<sub_delims>)\n\n" + " (?<ip_literal>\\[(?:\\g<ipv6address>|\\g<ipvfuture>)\\])\n" + " (?<ipvfuture>v\\g<hexdig>+\\.(?:\\g<unreserved>|\\g<sub_delims>|:)+)\n" + " (?<ipv6address>\n" + " (?:\\g<h16>:){6}\\g<ls32> |\n" + " ::(?:\\g<h16>:){5}\\g<ls32> |\n" + " (?: \\g<h16>)?::(?:\\g<h16>:){4}\\g<ls32> |\n" + " (?:(?:\\g<h16>:){0,1}\\g<h16>)?::(?:\\g<h16>:){3}\\g<ls32> |\n" + " (?:(?:\\g<h16>:){0,2}\\g<h16>)?::(?:\\g<h16>:){2}\\g<ls32> |\n" + " (?:(?:\\g<h16>:){0,3}\\g<h16>)?::(?:\\g<h16>:){1}\\g<ls32> |\n" + " (?:(?:\\g<h16>:){0,4}\\g<h16>)?:: \\g<ls32> |\n" + " (?:(?:\\g<h16>:){0,5}\\g<h16>)?:: \\g<h16> |\n" + " (?:(?:\\g<h16>:){0,6}\\g<h16>)?::\n" + " )\n" + " (?<h16>\\g<hexdig>{1,4})\n" + " (?<ls32>\\g<h16>:\\g<h16>|\\g<ipv4address>)\n\n" + " (?<ipv4address>\\g<dec_octet>\\.\\g<dec_octet>\\.\\g<dec_octet>\\.\\g<dec_octet>)\n" + " (?<dec_octet>\n" + " 25[0-5] | # 250-255\n" + " 2[0-4]\\g<digit> | # 200-249\n" + " 1\\g<digit>{2} | # 100-199\n" + " [1-9]\\g<digit> | # 10-99\n" + " \\g<digit> # 0-9\n" + " )\n" + " (?<reg_name>(?:\\g<unreserved>|\\g<pct_encoded>|\\g<sub_delims>)*)\n" + " \n" + " (?<path_abempty>(?:\\/\\g<segment>)*)\n" + " (?<path_absoloute>\\/(?:\\g<segment_nz>(?:\\/\\g<segment>)*))\n" + " (?<path_noscheme>\\g<segment_nz_nc>(?:\\/\\g<segment>)*)\n" + " (?<path_rootless>\\g<segment_nz>(?:\\/\\g<segment>)*)\n" + " (?<path_empty>)\n" + " \n" + " (?<segment> \\g<pchar>*)\n" + " (?<segment_nz> \\g<pchar>+)\n" + " (?<segment_nz_nc>(?:\\g<unreserved>|\\g<pct_encoded>|\\g<sub_delims>|@)+) # non-zero-length segment without any colon \":\"\n" + " \n" + " (?<pchar>\\g<unreserved>|\\g<pct_encoded>|\\g<sub_delims>|:|@)\n" + "){0}\n\n" + "(?<scheme>\n" + " \\g<alpha>\n" + " (?:\\g<alpha>|\\g<digit>|\\+|-|\\.)*\n" + ")\n" + ":\n" + "(?<heir_part>\n" + " (?:\n" + " \\/\\/\n" + " (?<authority>\n" + " (?:(?<userinfo>(?:\\g<unreserved>|\\g<pct_encoded>|\\g<sub_delims>|:)*)@)?\n" + " (?<host>\\g<ip_literal>|\\g<ipv4address>|\\g<reg_name>)\n" + " (?::(?<port>\\g<digit>*))?\n" + " )\n" + " )?\n" + " (?<path>(?(<authority>)\n" + " \\g<path_abempty> | # begins with \"/\" or is empty\n" + " (?:\n" + " \\g<path_absoloute> | # begins with \"/\" but not \"//\"\n" + " \\g<path_rootless> | # begins with a segment\n" + " \\g<path_noscheme> | # begins with a non-colon segment\n" + " \\g<path_empty> # zero characters\n" + " )\n" + " ))\n" + ")\n" + "(?:\\?(?<query>(?:\\g<pchar>|\\/|\\?)*))?\n" + "(?:\\#(?<fragment>(?:\\g<pchar>|\\/|\\?)*))?"; final String string = "ftp://ftp.is.co.za/rfc/rfc1808.txt\n" + "http://www.ietf.org/rfc/rfc2396.txt\n" + "ldap://[2001:db8::7]/c=GB?objectClass?one\n" + "mailto:John.Doe@example.com\n" + "news:comp.infosystems.www.servers.unix\n" + "tel:+1-816-555-1212\n" + "telnet://192.0.2.16:80/\n" + "urn:oasis:names:specification:docbook:dtd:xml:4.1.2\n"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | Pattern.COMMENTS); 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