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 = / - \d+ : (.+)/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp(' - \\d+ : (.+)', 'gm') const str = ` - 0 : <NSLayoutConstraint:0x6000035b77a0 UILayoutGuide:0x600002fe0e00''.centerY == UIFoundation.TitleSubtitleView:0x7f909a93c110.centerY (active)> - 1 : <NSLayoutConstraint:0x6000035b7750 H:|-(0)-[UILayoutGuide:0x600002fe0e00''] (active, names: '|':UIFoundation.TitleSubtitleView:0x7f909a93c110 )> - 2 : <NSLayoutConstraint:0x6000035b77f0 UILayoutGuide:0x600002fe0e00''.trailing == UIFoundation.TitleSubtitleView:0x7f909a93c110.trailing (active)> - 3 : <NSLayoutConstraint:0x6000035b7840 V:|-(>=0)-[UILayoutGuide:0x600002fe0e00''] (active, names: '|':UIFoundation.TitleSubtitleView:0x7f909a93c110 )> - 4 : <NSLayoutConstraint:0x6000035b7890 V:|-(0@250)-[UILayoutGuide:0x600002fe0e00''] priority:250 (active, names: '|':UIFoundation.TitleSubtitleView:0x7f909a93c110 )> - 5 : <NSLayoutConstraint:0x6000035b78e0 UILayoutGuide:0x600002fe0ee0''.top == UILayoutGuide:0x600002fe0e00''.top + 12 (active)> - 6 : <NSLayoutConstraint:0x6000035b7930 UILayoutGuide:0x600002fe0ee0''.bottom == UILayoutGuide:0x600002fe0e00''.bottom - 12 (active)> - 7 : <NSLayoutConstraint:0x6000035b7980 UILayoutGuide:0x600002fe0ee0''.leading == UILayoutGuide:0x600002fe0e00''.leading + 16 (active)> - 8 : <NSLayoutConstraint:0x6000035b79d0 UILayoutGuide:0x600002fe0ee0''.trailing == UILayoutGuide:0x600002fe0e00''.trailing - 16 (active)> - 9 : <NSLayoutConstraint:0x6000035b7a70 UIFoundation.FadingLabel:0x7f909a9334e0.top == UILayoutGuide:0x600002fe0ee0''.top (active)> - 10 : <NSLayoutConstraint:0x6000035b7b10 UIFoundation.FadingLabel:0x7f909a9334e0.leading == UILayoutGuide:0x600002fe0ee0''.leading (active)> - 11 : <NSLayoutConstraint:0x6000035b7b60 UIFoundation.FadingLabel:0x7f909a9334e0.trailing == UILayoutGuide:0x600002fe0ee0''.trailing (active)> - 12 : <NSLayoutConstraint:0x6000035b7a20 V:[UIFoundation.FadingLabel:0x7f909a9334e0]-(8)-[UIFoundation.FadingLabel:0x7f909a81b610] (active)> - 13 : <NSLayoutConstraint:0x6000035b7c00 UIFoundation.FadingLabel:0x7f909a81b610.leading == UILayoutGuide:0x600002fe0ee0''.leading (active)> - 14 : <NSLayoutConstraint:0x6000035b7c50 UIFoundation.FadingLabel:0x7f909a81b610.trailing == UILayoutGuide:0x600002fe0ee0''.trailing (active)> - 15 : <NSLayoutConstraint:0x6000035b7ca0 UIFoundation.FadingLabel:0x7f909a9334e0.bottom <= UILayoutGuide:0x600002fe0ee0''.bottom (active)> - 16 : <NSLayoutConstraint:0x6000035b7ac0 UIFoundation.FadingLabel:0x7f909a9334e0.bottom == UILayoutGuide:0x600002fe0ee0''.bottom (active)>`; const subst = `"$1",`; // 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