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

/
/
gxm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /(?(DEFINE) (?<varchar> [[:alnum:]] | [-_] ) (?<funcname> [[:alpha:]](?&varchar)* ) (?<varname> \$(?&funcname) ) (?<typepart> [[:alpha:][[:alnum:]]*) (?<typename> \[ (?&typepart) ( \.(?&typepart) )* \] ) (?<arg> (?&typename)? \s* (?&varname) ) (?<arglist> (?&arg) ( \s*,\s* (?&arg) )* ) (?<args> ( \( (?&arglist)? \) )? ) (?<func_decl> ^ \s* function \s+ (?&funcname) \s* (?&args) \s* \{ ) ) (?&func_decl)/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?(DEFINE) (?<varchar> [[:alnum:]] | [-_] ) (?<funcname> [[:alpha:]](?&varchar)* ) (?<varname> \\$(?&funcname) ) (?<typepart> [[:alpha:][[:alnum:]]*) (?<typename> \\[ (?&typepart) ( \\.(?&typepart) )* \\] ) (?<arg> (?&typename)? \\s* (?&varname) ) (?<arglist> (?&arg) ( \\s*,\\s* (?&arg) )* ) (?<args> ( \\( (?&arglist)? \\) )? ) (?<func_decl> ^ \\s* function \\s+ (?&funcname) \\s* (?&args) \\s* \\{ ) ) (?&func_decl)', 'gm') const str = `function Main (\$x, [string]\$y) { function Get-Content { function main_- () { function main([string.Array] \$mfd_) { `; 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