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
Processing...

Test String

Code Generator

Language

Generated Code

re = /(?(DEFINE) (?<marker>\b[A-Z][-\w]*\b) (?<ws>[\ \t]+) (?<needle>\b(?:Study|Test)) (?<pre>(?:(?&marker)(?&ws))+) (?<post>(?:(?&ws)(?&marker))+) (?<before>(?&pre)(?&needle)) (?<after>(?&needle)(?&post)) (?<both>(?&pre)(?&needle)(?&post)) ) (?&both)|(?&before)|(?&after)/mx str = ' I have been analyzing large amounts of text data. This is what I got so far: (([A-Z][\\w-]*)+\\s+(\\b(Study|Test)\\b)(\\s[A-Z][\\w-]*)*)|(\\b(Study|Test)\\b)(\\s[A-Z][\\w-]*)+ Types of phrases I would like to capture: Europe National Longitudinal Study Longitudinal Study Study Initiative Longitudinal Study Initiative I want to capture the word \'Study\' or \'Test\' ONLY if it is surrounded by the words starting with a capital letter. The ideal regex would achieve all of this + it would ignore\\escape certain words like \'of\' or \'the\'. *the above regex is super slow with the str.findall function, I guess there must be a better solution ** I used https://regex101.com for testing and then run it in Jupyter, Python 3 ' # 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