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

/
/
g

Test String

Code Generator

Generated Code

const regex = /(?|([a-zA-Z0-9]+)\(([a-zA-Z\s]+)\)|\(([a-zA-Z\s]+)\)([a-zA-Z0-9]+))|(\b[\(|\{|\[|\«]+[\w\s]*[\)|\}|\]|\»]+)/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?|([a-zA-Z0-9]+)\\(([a-zA-Z\\s]+)\\)|\\(([a-zA-Z\\s]+)\\)([a-zA-Z0-9]+))|(\\b[\\(|\\{|\\[|\\«]+[\\w\\s]*[\\)|\\}|\\]|\\»]+)', 'g') const str = `(Weather) is good. // not need to mark this beacuase this word correct word Weath(er) is good. // mark Weath(er is good). // mark Weather (is) (good). My name is Rah(eel) // mark Best pro(duct) // mark (Weather is good) // not need to mark this beacuase this word konown word we(ather) (weath)er is good. // mark (weath)er // mark weather(is fine) weather is good {weather is good} //not need to mark correct weat{er is good} // mark we{ather} is fine // mark {weathe}r is fine // i want to mark this word {weather is fin}e // i want to mark this word [weather is good] //not need to mark correct weat[her is good] // mark we[ather] is fine // mark [weathe]r is fine // i want to mark this word [weather is f]ine // i want to mark this word we[ather] is fine // mark «weather is good» //not need to mark weat«her is good» // mark we«ather» is fine // mark «weat»her is fine // i want to mark this word «weather is fi»ne // i want to mark this word `; // 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