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

r"
"
gm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

$re = '/\s*\d+\s*(?:units?|times?(?:\s+(?:a|per)\s+|\s*/\s*)(?:d(?:ay)?|w(?:ee)?k|month|y(?:ea)?r?))/m'; $str = 'inJECTable 1234 Eprex DOSE 4000 units on NONd department 6789 DOSE 8000 units on DIALYSIS days - IV Interm\', inJECTable 4321 Eprex DOSE - 3 times/wk on NONdialysis day\', insulin MixTARD 30/70 - inJECTable 46 units\', insulin ISOPHANE -- InsulaTARD Vial - inJECTable 56 units SC SubCutaneous\', 1-alfacalcidol DOSE 1 mcg - 3 times a week - IV Intermittent\', jevity liquid - FEEDS PO Jevity - 237 mL - 1 times per day\', 1-alfacalcidol DOSE 1 mcg - 3 times per week - IV Intermittent\', 1-supported DOSE 1 mcg - 1 time/day - IV Intermittent\', 1-testpackage DOSE 1 mcg - 1 time a day - IV Intermittent ///3 times a day, 3 time/wk, 3 times per day, 3 times a month, 3 times/month'; $subst = ""; $result = preg_replace($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