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

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /\A(?:^(?!.*\bLecture\b).*\r?\n)*|^\r?\n|^.*\r?\n(?![\s\S]*\bLecture\b)/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\A(?:^(?!.*\\bLecture\\b).*\\r?\\n)*|^\\r?\\n|^.*\\r?\\n(?![\\s\\S]*\\bLecture\\b)', 'gm') const str = `My Dashboard Fnfjfjf. random test 00:50 1:01:56 My Notes No data found. Change Language + English Submit Estimation of Working Capital Lecture 1 Estimation of Working Capital Lecture 2 Estimation of Working Capital Lecture 3 Money Market Lecture 254 Money Market Lecture 255 Money Market Lecture 256 International Trade Lecture 257 International Trade Lecture 258 International Trade Lecture 259 Terms And Conditions 84749473837373 Random text fifjfofifofjfkfkf `; const subst = ``; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

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