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 = "^(?<location>[A-Za-z]+)[-_][A-Z]{1,2}\\d"; final String string = "BMD-R1\n" + "BMD-R2\n" + "BTN-R1\n" + "BTN-R1-SW\n" + "BTN-R2\n" + "BTN-R2-SW\n" + "CentralOCS-R1\n" + "CentralOCS-R1-SW\n" + "CentralOCS-R2\n" + "CentralOCS-R2-SW\n" + "CentralOCS-SW3\n" + "CentralOCS-SW4\n" + "CLJ-R1\n" + "CLJ-R2\n" + "CS-HPOV-MLS1\n" + "CS-HPOV-MLS2\n" + "CTN-R1\n" + "CTN-R2\n" + "EKV-OTC-MLS1\n" + "GOS-R1\n" + "GOS-R2\n" + "GVL-R1\n" + "GVL-R2\n" + "ING-R1\n" + "LAW-R1\n" + "LCS-R1\n" + "LCS-R2\n" + "LIV-R1\n" + "Mascot_R1\n" + "Mascot_R2\n" + "Mascot_SW1\n" + "Mascot_SW2\n" + "Mascot_SW3\n" + "MST-R1\n" + "MST-R2\n" + "MTV-R1\n" + "MTV-R2\n" + "OSS-FW1 (FO)\n" + "OSS-FW1 (Pri)\n" + "PEN-R1\n" + "PEN-R2\n" + "Pitt_R1\n" + "ROC-FW1\n" + "ROC-HPDM-SW1\n" + "ROC-PUB-MLS1\n" + "ROC-PUB-MLS2\n" + "ROC-RCS-SW \n" + "SM-ER-SW1 \n" + "SM-ER-SW2 \n" + "SM-FW1 (FO)\n" + "SM-FW1 (Pri)\n" + "SM-PUB-R1\n" + "SM-PUB-R1-SW\n" + "SM-PUB-R2\n" + "SM-PUB-R2-SW\n" + "SM-RCS-R1\n" + "SM-RCS-R2\n" + "SM-RCS-SW1\n" + "SM-RCS-SW2\n" + "ST-ER-SW1 \n" + "ST-ER-SW2 \n" + "ST-FW1 (FO)\n" + "ST-FW1 (Pri)\n" + "STM-R1\n" + "STM-R2\n" + "ST-OSS-MAIN-R1\n" + "ST-OSS-MAIN-R2\n" + "ST-OSS-PUB-R1\n" + "ST-OSS-PUB-R1-SW\n" + "ST-OSS-PUB-R2\n" + "ST-OSS-PUB-R2-SW\n" + "ST-PUB-MLS1\n" + "ST-PUB-MLS2\n" + "ST-PUB-R1\n" + "ST-PUB-R2\n" + "ST-RCS-R1\n" + "ST-RCS-R2\n" + "ST-RCS-SW1\n" + "ST-RCS-SW2\n" + "TES-SW1\n" + "Waterfall_SW1\n" + "Waterfall_SW2\n" + "Waterfall-R1\n" + "Waterfall-R2\n" + "WolloFW_R1\n" + "WolloFW_R2\n" + "WolloFW_SW\n" + "WYG-R1\n" + "WYG-R2\n" + "Wynyard_R1\n" + "Wynyard_R2\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