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

/
/
gm

Test String

Code Generator

Language

Generated Code

re = /(\\usepackage{(?:tikz|pgfplots)}|\\(?:tikzset|pgfplotsset){(?:[^{}]+|{(?:[^{}]+|{(?:[^{}]+|{[^{}]+})+})+})+}|\\(?:usetikzlibrary|usepgfplotslibrary){[\w\.,]+}|\\definecolor{\w+}{\w+}{[^}]+}|\\colorlet{\w+}{{[^}]+}})/m str = '\\documentclass{article} \\usepackage{tikz} \\usetikzlibrary{decorations.markings} \\tikzset{ ->-/.style={ postaction=decorate, decoration={markings,mark=at position #1 with \\arrow{>}} } } \\begin{document} \\begin{center} \\begin{tikzpicture} \\draw[->-=0.5] (0,0) -- (3,-2); \\end{tikzpicture} \\end{center} \\end{document}' # 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