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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Generated Code

$re = '/^Hi.*Page (\d+).*\n(.*)/m'; $str = 'Notes and highlights for Outlive Attia MD, Peter Part I Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 10 · Location 150 In 1900 , life expectancy hovered somewhere south of age fifty , and most people were likely to die from “ fast ” causes : accidents , injuries , and infectious diseases of various kinds . Since then , slow death has supplanted fast death . The majority of people reading this book can expect to die somewhere in their seventies or eighties , give or take , and almost all from “ slow ” causes . Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 10 · Location 154 Four Horsemen : heart disease , cancer , neurodegenerative disease , or type 2 diabetes and related metabolic dysfunction . Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 10 · Location 155 we must understand and confront these causes of slow death . Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 10 · Location 158 Healthspan is typically defined as the period of life when we are free from disability or disease , Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 14 · Location 215 It is absurd and harmful to treat this disease like a cold or a broken bone , where you either have it or you don’t ; it’s not binary . Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 14 · Location 218 Changing that mindset must be our first step in attacking slow death . We want to delay or prevent these conditions so that we can live longer without disease , rather than lingering with disease . Highlight (yellow) - Chapter 1: The Long Game: From Fast Death to Slow Death > Page 17 · Location 270 Exercise is by far the most potent longevity “ drug . ” No other intervention does nearly as much to prolong our lifespan and preserve our cognitive and physical function .'; $subst = "> $2 [@attia:2023 p.$1]\n"; $result = preg_replace($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