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

const regex = /^(?<location>[A-Za-z]+)[-_][A-Z]{1,2}\d/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('^(?<location>[A-Za-z]+)[-_][A-Z]{1,2}\\d', 'gm') const str = `BMD-R1 BMD-R2 BTN-R1 BTN-R1-SW BTN-R2 BTN-R2-SW CentralOCS-R1 CentralOCS-R1-SW CentralOCS-R2 CentralOCS-R2-SW CentralOCS-SW3 CentralOCS-SW4 CLJ-R1 CLJ-R2 CS-HPOV-MLS1 CS-HPOV-MLS2 CTN-R1 CTN-R2 EKV-OTC-MLS1 GOS-R1 GOS-R2 GVL-R1 GVL-R2 ING-R1 LAW-R1 LCS-R1 LCS-R2 LIV-R1 Mascot_R1 Mascot_R2 Mascot_SW1 Mascot_SW2 Mascot_SW3 MST-R1 MST-R2 MTV-R1 MTV-R2 OSS-FW1 (FO) OSS-FW1 (Pri) PEN-R1 PEN-R2 Pitt_R1 ROC-FW1 ROC-HPDM-SW1 ROC-PUB-MLS1 ROC-PUB-MLS2 ROC-RCS-SW SM-ER-SW1 SM-ER-SW2 SM-FW1 (FO) SM-FW1 (Pri) SM-PUB-R1 SM-PUB-R1-SW SM-PUB-R2 SM-PUB-R2-SW SM-RCS-R1 SM-RCS-R2 SM-RCS-SW1 SM-RCS-SW2 ST-ER-SW1 ST-ER-SW2 ST-FW1 (FO) ST-FW1 (Pri) STM-R1 STM-R2 ST-OSS-MAIN-R1 ST-OSS-MAIN-R2 ST-OSS-PUB-R1 ST-OSS-PUB-R1-SW ST-OSS-PUB-R2 ST-OSS-PUB-R2-SW ST-PUB-MLS1 ST-PUB-MLS2 ST-PUB-R1 ST-PUB-R2 ST-RCS-R1 ST-RCS-R2 ST-RCS-SW1 ST-RCS-SW2 TES-SW1 Waterfall_SW1 Waterfall_SW2 Waterfall-R1 Waterfall-R2 WolloFW_R1 WolloFW_R2 WolloFW_SW WYG-R1 WYG-R2 Wynyard_R1 Wynyard_R2 `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions