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

~
~
xsmg

Test String

Code Generator

Generated Code

const regex = new RegExp('\\s* # white spaces ########################## KEYS START ########################## (?: # We\\\\'ll use this to make keys optional (?P<keys> # named group: keys \\d+ # match digits | # or "(?(?=\\\\\\\\")..|[^"])*" # match string between "", works even 4 escaped ones "hello \\" world" | # or \\\\'(?(?=\\\\\\\\\\\\')..|[^\\\\'])*\\\\' # match string between \\\\'\\\\', same as above :p | # or \\$\\w+(?:\\[(?:[^[\\]]|(?R))*\\])* # match variables $_POST, $var, $var["foo"], $var["foo"]["bar"], $foo[$bar["fail"]] ) # close group: keys ########################## KEYS END ########################## \\s* # white spaces => # match => )? # make keys optional \\s* # white spaces ########################## VALUES START ########################## (?P<values> # named group: values \\d+ # match digits | # or "(?(?=\\\\\\\\")..|[^"])*" # match string between "", works even 4 escaped ones "hello \\" world" | # or \\\\'(?(?=\\\\\\\\\\\\')..|[^\\\\'])*\\\\' # match string between \\\\'\\\\', same as above :p | # or \\$\\w+(?:\\[(?:[^[\\]]|(?R))*\\])* # match variables $_POST, $var, $var["foo"], $var["foo"]["bar"], $foo[$bar["fail"]] | # or array\\s*\\((?:[^()]|(?R))*\\) # match an array() | # or \\[(?:[^[\\]]|(?R))*\\] # match an array, new PHP array syntax: [1, 3, 5] is the same as array(1,3,5) | # or (?:function\\s+)?\\w+\\s* # match functions: helloWorld, function name (?:\\((?:[^()]|(?R))*\\)) # match function parameters (wut), (), (array(1,2,4)) (?:(?:\\s*use\\s*\\((?:[^()]|(?R))*\\)\\s*)? # match use(&$var), use($foo, $bar) (optionally) \\{(?:[^{}]|(?R))*\\} # match { whatever} )?;? # match ; (optionally) ) # close group: values ########################## VALUES END ########################## \\s* # white spaces', 'smg') const str = `0 => "a", 123 => 123, 1234, 'got problem ?', "a" => \$GlobalScopeVar, \$test_further => function test(\$noway){echo "this works too !!!";}, "yellow" => "blue", "b" => array("nested"=>array(1,2,3), "nested"=>array(1,2,3),"nested"=>array(1,2,3)), "c" => function() use (&\$VAR) { return isset(\$VAR) ? "defined" : "undefined" ; }, "bug",\$var = \$_POST["test]; "fixed", "mwahahahaa" => "Yeaaaah", \$_POST["hello"][\\'world\\'] => array("is", "actually", "An array !")`; // 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