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 = /(<a\b[^<]*?|(?<!^)\G)([^\/]*?)%20(?=(?![^\/]*\.jpg">)[^\/"]*">)/ str = '<a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/34%20-%20kv34%20-%20tomba%20di%20thumtmose%20iii"> KV34 Tomba di Thutmose III</a>:</b> Nella foto, la pianta della tomba</font></p> </td> </tr> </tbody></table> </div> <div align="center"> <div align="center"> <table border="1" width="96%" id="table4"> <tbody align="left"><tr> <td width="11%" align="center"> <a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/06%20antichi%20egizi%20-%20Tomba%20di%20Amenofi.jpg"> <img border="0" src="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/06%20antichi%20egizi%20-%20Tomba%20di%20Amenofi%20ante.jpg" width="80" height="64" alt="/06 antichi egizi - Tomba di Amenofi" /></a></td> <td width="87%" class="style4"> <p class="style3"> <b><a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/35%20KV35%20Tomba%20di%20Amenofi%20II">KV35 Tomba di Amenofi II</a>; </b> Nella foto, il re davanti alla dea Hathor che gli offra il segno della vita.</p> </td> </tr> <tr> <td width="11%" align="center"> <a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/24%20antichi%20egizi%20-%20tomba%20di%20Horemhab.jpg"> <img border="0" src="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/24%20antichi%20egizi%20-%20tomba%20di%20Horemhab%20ante.jpg" width="80" height="59" alt="24 antichi egizi - tomba di Horemhab" /></a></td> <td width="87%" class="style4"> <div class="style3"> <b><a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/57%20kv57%20tomba%20di%20horemhab"> KV 57Tomba di Horemhab</a><font face="Arial" size="2">: </font></b><font face="Arial" size="2">Nella foto, il faraone è raffigurato di fronte a varie divinità</font></div> </td> </tr> <tr> <td width="11%" align="center"> <a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/09%20antichi%20egizi%20-%20Tomba%20di%20Tutankhamen.jpg"> <img border="0" src="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/09%20antichi%20egizi%20-%20Tomba%20di%20Tutankhamen%20ante.jpg" width="80" height="92" alt="09 antichi egizi - Tomba di Tutankhamen" /></a></td> <td width="87%" class="style4"> <b><a href="http://example.com/path/to-some-folder/another%20folder/one%20more520folder/uploads/2012/02/some%20folder/another%20folder/62%20kv62%20tomba%20di%20tutankhamen">KV62 Tomba di Tutankhamen:</a></b> Nella foto, <font face="Arial" size="2">un particolare della decorazione, con la barca solare ed i babbuini che alludono alla prima ora del libro dell\'Amduat.</font></td> </tr> <tr> <td' subst = '\\1\\2-' result = str.gsub(re, subst) # Print the result of the substitution puts 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 Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html