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 = /\"user\":\s+\{\s+\"id\":\s+(?<user_id>[^,]+)/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\"user\\":\\s+\\{\\s+\\"id\\":\\s+(?<user_id>[^,]+)', 'gm') const str = `"aepassword": "kmdAkcu)n>Ec_.a(m5P7?8-n", "aeci": { "outgoing_server": "mailrv.aaa.com", "email_footer": "C:\\\\ProgramData\\\\bbb\\\\AutomationNote\\\\Email\\\\aa_Mail_Footer.png", "email_header": "C:\\\\ProgramData\\\\bbb\\\\AutomationNote\\\\Email\\\\aa_Mail_Header.png", "signature": "C:\\\\ProgramData\\\\bbb\\\\Automation\\\\Email\\\\bb_Email_Signature.txt", "requires_authentication": "false", "reply-to": "us@aaa.com", "primaryaddress": "ussdev@aaa.com", "host": "ussdev@bbb.com", "entity_alternate_names": "usdev@aaa.com", "outgoing_port": "2675", "entityid": "wmid-1607548215055521", "name": "bbb_MailBox", "entitytype": "Sub-System", "entitytype": "Workplace", "technology": "O736i85", "tenantid": 1000011, "cloudprovider": "", "satellite": "sat-16107579705752592", "resourceid": null, "UDetails": { "creds": { "email": "NA" }, "id": 14, "name": "N/A" }, "encryptionKey": "5inqhg7ckj7klk2w4osk0", "user": { "id": 5, "name": "CRI Admin", "employeecode": "125", "email": "admin@aaa.com" },`; // 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