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

Substitution
Processing...

Code Generator

Language

Generated Code

const regex = /("(post\s*(office)?)?\s*box\s*[#-]?\s*(\d+)?"|"[\w\s]*?p(ost)?\s*[.-]?\s*o?\s*\.?\s*b?(ox)?\.?\s*(\d+)?"|"\s*number\s*\d+")/gim; // Alternative syntax using RegExp constructor // const regex = new RegExp('("(post\\s*(office)?)?\\s*box\\s*[#-]?\\s*(\\d+)?"|"[\\w\\s]*?p(ost)?\\s*[.-]?\\s*o?\\s*\\.?\\s*b?(ox)?\\.?\\s*(\\d+)?"|"\\s*number\\s*\\d+")', 'gim') const str = ` "Box 123", "Box-122", "Box122", "HC73 P.O. Box 217", "P O Box125", "P. O. Box", "P.O 123", "P.O. Box 123", "P.O. Box", "P.O.B 123", "P.O.B. 123", "P.O.B.", "POB 123", "POB", "POBOX123", "Po Box", "Post 123", "Post Box 123", "Post Office Box 123", "Post Office Box", "box #123", "box 122", "box 123", "number 123", "p box", "p-o box", "post office box" "The Postal Road", "Box Hill", "123 Some Street", "Controller's Office", "pollo St.", "123 box canyon rd", "777 Post Oak Blvd", "PSC 477 Box 396", "RR 1 Box 1020"`; const subst = ``; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', 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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions