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]
  • Character class intersection
    [\w&&[^\d]]
  • 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
Processing...

Test String

Code Generator

Language

Generated Code

re = /^(\+ *|- *)?((?!0+)\d*?|(?!0{2,})\d*?\.(?!0+)\d*?)('|")$|^(\+ *|- *)? *(?!0+)\d+?' *-? *(\d+?|\d*?\.\d*?)"$|^((\+ *|- *)?((?!0+)|0 )\d*? *(?!0+)\d+?\/(?!0+)\d+?('|"))$/m str = ' - + - x 20\'-4" + 20\' - 20\' 20\'3" 20\'-3" 20\' - 40" -20\'-20" 20\'00" 20.45" 20.45\' 00.45\' 00.45" 00" 00\' +20\' - 0.45" 20\' - .45" .20\'-4" 0.30\'-4" 20\' 20\'P 20" 20"P 0.20\' .20\' a\' b" - 20 1/2\' + 20 22/128" 20 0/2" 20 00/12\' -1/2" + 1/2\' 0/2" 00/22" + 01/2" 23 00/30\' 23 12/03\' 23 02/20" 0 2/3\' 00 2/3\' - 11 2/3\' 2 22\' 2 22/03\' 2 3/2 23 00/30 23 12/03 23 02/20 23/34" 23/23.4" asf sf" ' # Print the match result str.scan(re) do |match| puts match.to_s end

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