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
Processing...

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 = "^(?P<alb_type>(https?|h2|wss?))\\s*(?P<alb_timestamp>[^\\s]+)\\s*(?P<alb_elb>[^\\s]+)\\s*(?P<alb_client_addr>[^:]+):\\s*(?P<alb_client_port>[^\\s]+)\\s*(?P<alb_target_addr>[^:]+):(?P<alb_target_port>[^\\s]+)\\s*(?P<alb_request_processing_time>[^\\s]+)\\s*(?P<alb_target_processing_time>[^\\s]+)\\s*(?P<alb_response_processing_time>[^\\s]+)\\s*(?P<alb_elb_status_code>[^\\s]+)\\s*(?P<alb_target_status_code>[^\\s]+)\\s*(?P<alb_received_bytes>[^\\s]+)\\s*(?P<alb_sent_bytes>[^\\s]+)\\s*\"(?P<alb_request>.*?)\"\\s+\"(?P<alb_user_agent>[^\\\"]+)\"\\s*(?P<alb_ssl_cipher>[^\\s]+)\\s*(?P<alb_ssl_protocol>[^\\s]+)\\s*(?P<alb_target_group_arn>[^\\s]+)\\s*\"(?P<alb_trace_id>[^\\\"]+)\"\\s*\"(?P<alb_domain_name>[a-zA-Z0-9\\.\\-:]+)\"\\s*\"(?P<alb_chosen_cert_arn>[^\\\"]+)\"\\s*(?P<alb_matched_rule_priority>[^\\s]+)\\s*(?P<alb_request_creation_time>[^\\s]+)\\s*\\s*\"(?P<alb_actions_executed>[^\\s]+)\"\\s*\"(?P<alb_redirect_url>[^\\s]+)\"\\s*\"(?P<alb_error_reason>[^\\\"]+)\"\\s*\"?(?P<alb_target_port_list>[0-9 :\\.-]+)\"?\\s*\"?(?P<alb_target_status_code_list>[0-9 -]+)\"?"; final String string = "http 2018-07-02T22:23:00.186641Z app/my-loadbalancer/50dc6c495c0c9188 \n" + "192.168.131.39:2817 10.0.0.1:80 0.000 0.001 0.000 200 200 34 366 \n" + "\"GET http://www.example.com:80/ HTTP/1.1\" \"curl/7.46.0\" - - \n" + "arn:aws:elasticloadbalancing:us-east-2:123456789012:targetgroup/my-targets/73e2d6bc24d8a067\n" + "\"Root=1-58337262-36d228ad5d99923122bbe354\" \"-\" \"-\" \n" + "0 2018-07-02T22:22:48.364000Z \"forward\" \"-\" \"-\" 80 200 \n\n" + "ws 2018-07-02T22:23:00.186641Z app/my-loadbalancer/50dc6c495c0c9188 \n" + "10.0.0.140:40914 10.0.1.192:8010 0.001 0.003 0.000 101 101 218 587 \n" + "\"GET http://10.0.0.30:80/ HTTP/1.1\" \"-\" - - \n" + "arn:aws:elasticloadbalancing:us-east-2:123456789012:targetgroup/my-targets/73e2d6bc24d8a067\n" + "\"Root=1-58337364-23a8c76965a2ef7629b185e3\" \"-\" \"-\"\n" + "1 2018-07-02T22:22:48.364000Z \"forward\" \"-\" \"-\" 80 200\n\n" + "wss 2018-07-02T22:23:00.186641Z app/my-loadbalancer/50dc6c495c0c9188 \n" + "10.0.0.140:44244 10.0.0.171:8010 0.000 0.001 0.000 101 101 218 786\n" + "\"GET https://10.0.0.30:443/ HTTP/1.1\" \"-\" ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 \n" + "arn:aws:elasticloadbalancing:us-west-2:123456789012:targetgroup/my-targets/73e2d6bc24d8a067\n" + "\"Root=1-58337364-23a8c76965a2ef7629b185e3\" \"-\" \"-\"\n" + "1 2018-07-02T22:22:48.364000Z \"forward\" \"-\" \"-\" \"44244\" \"101\"\n\n\n\n\n\n\n"; 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