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

/
/
igmX

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 = "(?#URI)^(?#\n" + " Scheme )(?<Scheme>[a-z][a-z0-9\\+\\-\\.]*):(?#\n" + " HeirPart)(?<HierPart>\\/\\/(?#\n" + " Authority)(?<Authority>(?#\n" + " UserInfo)((?<UserInfo>(\\%[0-9a-f][0-9a-f]|[a-z0-9\\-\\.\\_\\~]|[\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=]|\\:)*)\\@)?(?#\n" + " Host )(?<Host>(?#\n" + " IP Literal)\\[((?#\n" + " IPv6 Address )(?<IPv6>((?<IPv6_1_R_H16>[0-9a-f]{1,4})\\:){6,6}(?<IPV6_1_R_LS32>((?<IPV6_1_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_1_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_1_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_1_R_LS32_H16_2>[0-9a-f]{1,4}))|\\:\\:((?<IPV6_2_R_H16>[0-9a-f]{1,4})\\:){5,5}(?<IPV6_2_R_LS32>((?<IPV6_2_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_2_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_2_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_2_R_LS32_H16_2>[0-9a-f]{1,4}))|(?<IPV6_3_L_H16>[0-9a-f]{1,4})?\\:\\:((?<IPV6_3_R_H16>[0-9a-f]{1,4})\\:){4,4}(?<IPV6_3_R_LS32>((?<IPV6_3_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_3_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_3_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_3_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_4_L_H16_REPEAT>[0-9a-f]{1,4})\\:)?(?<IPV6_4_L_H16>[0-9a-f]{1,4}))?\\:\\:((?<IPV6_4_R_H16>[0-9a-f]{1,4})\\:){3,3}(?<IPV6_4_R_LS32>((?<IPV6_4_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_4_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_4_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_4_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_5_L_H16_REPEAT>[0-9a-f]{1,4})\\:){0,2}(?<IPV6_5_L_H16>[0-9a-f]{1,4}))?\\:\\:((?<IPV6_5_R_H16>[0-9a-f]{1,4})\\:){2,2}(?<IPV6_5_R_LS32>((?<IPV6_5_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_5_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_5_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_5_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_6_L_H16_REPEAT>[0-9a-f]{1,4})\\:){0,3}(?<IPV6_6_L_H16>[0-9a-f]{1,4}))?\\:\\:(?<IPV6_6_R_H16>[0-9a-f]{1,4})\\:(?<IPV6_6_R_LS32>((?<IPV6_6_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_6_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_6_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_6_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_7_L_H16_REPEAT>[0-9a-f]{1,4})\\:){0,4}(?<IPV6_7_L_H16>[0-9a-f]{1,4}))?\\:\\:(?<IPV6_7_R_LS32>((?<IPV6_7_R_LS32_IPV4_DEC_OCTET>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}(?<IPV6_7_R_LS32_IPV4_DEC_OCTET_>[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?<IPV6_7_R_LS32_H16_1>[0-9a-f]{1,4})\\:(?<IPV6_7_R_LS32_H16_2>[0-9a-f]{1,4}))|(((?<IPV6_8_L_H16_REPEAT>[0-9a-f]{1,4})\\:){0,5}(?<IPV6_8_L_H16>[0-9a-f]{1,4}))?\\:\\:(?<IPV6_8_R_H16>[0-9a-f]{1,4})|(((?<IPV6_9_L_H16_REPEAT>[0-9a-f]{1,4})\\:){0,6}(?<IPV6_9_L_H16>[0-9a-f]{1,4}))?\\:\\:)|(?#\n" + " IPvFuture Address)v[a-f0-9]+\\.([a-z0-9\\-\\.\\_\\~]|[\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=]|\\:)+(?#\n" + " ))\\]|(?#\n" + " IPv4 Address)(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\\.){3,3}([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])|(?#\n" + " RegName)([a-z0-9\\-\\.\\_\\~]|\\%[0-9a-f][0-9a-f]|[\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=])*(?#\n" + " ))(?#\n" + " Port )(:(?<Port>[0-9]+))?(?#\n" + " ))(?#\n" + " Path )(?<Path>(\\/([a-z0-9\\-\\.\\_\\~\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=\\:\\@]|(%[a-f0-9]{2,2}))*)*)(?#\n" + " ))(?#\n" + " Query )(?<Query>\\?([a-z0-9\\-\\.\\_\\~\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=\\:\\@\\/\\?]|(%[a-f0-9]{2,2}))*)?(?#\n" + " Fragment)(?<Fragment>#([a-z0-9\\-\\.\\_\\~\\!\\$\\&\\'\\(\\)\\*\\+\\,\\;\\=\\:\\@\\/\\?]|(%[a-f0-9]{2,2}))*)?(?#\n" + ")$"; final String string = "http://helloworld.com/\n" + "foo+://example.com:8042/over/there?name=ferret#nose\n" + "foo+://andrewj:myPassword:mySecondPassword@example.com:8042/over/there?name=ferret#nose\n\n" + "urn:example:animal:ferret:nose\n\n" + "http://10.15.20.73/\n" + "http://user.@com/"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | 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