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

/
/
g

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

$re = '/url\(\'[\.]{2}\//'; $str = '@font-face{font-family:\'FontAwesome\';src:url(\'../fonts/fontawesome-webfont.eot?v=4.1.0\');src:url(\'../fonts/fontawesome-webfont.eot?#iefix&v=4.1.0\') format(\'embedded-opentype\'),url(\'../fonts/fontawesome-webfont.woff?v=4.1.0\') format(\'woff\'),url(\'../fonts/fontawesome-webfont.ttf?v=4.1.0\') format(\'truetype\'),url(\'../fonts/fontawesome-webfont.svg?v=4.1.0#fontawesomeregular\') format(\'svg\');font-weight:normal;font-style:normal} .preview .fa{display:inline-block;font-family:FontAwesome;font-style:normal;font-weight:normal;line-height:1;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale} .preview .fa-lg{font-size:1.33333333em;line-height:.75em;vertical-align:-15%} .preview .fa-2x{font-size:2em} .preview .fa-3x{font-size:3em} .preview .fa-4x{font-size:4em} .preview .fa-5x{font-size:5em} .preview .fa-fw{width:1.28571429em;text-align:center} .preview .fa-ul{padding-left:0;margin-left:2.14285714em;list-style-type:none} .preview .fa-ul>li{position:relative'; $subst = "url(//en.wikipedia.org/${1})"; $result = preg_replace($re, $subst, $str); echo "The result of the substitution is ".$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 PHP, please visit: http://php.net/manual/en/ref.pcre.php