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

import Foundation let pattern = ##"(?P<Element><(?P<TagName>[:_A-z][-.0-9:_A-z\xB7]*)(?:[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*[\x09\x0A\x0D\x20]*=[\x09\x0A\x0D\x20]*(?:"(?:[^<&"]|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*"|'(?:[^<&']|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*'))*[\x09\x0A\x0D\x20]*(?:>(?:(?:[^<&\]]|](?!]>))*(?:(?:(?P>Element)|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));|<!\[CDATA\[(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x5D]|](?!]>))*]]>|<\?[:_A-z][-.0-9:_A-z\xB7]*(?<!(?i:\?xml))(?:[\x09\x0A\x0D\x20]+(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x3F]|\?(?!>))*)?\?>|<!--(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x2D]|-(?!-))*-->)(?:[^<&\]]|](?!]>))*)*)<\/(?P=TagName)[\x09\x0A\x0D\x20]*|\/)>)|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));|<!\[CDATA\[(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x5D]|](?!]>))*]]>|<\?[:_A-z][-.0-9:_A-z\xB7]*(?<!(?i:\?xml))(?:[\x09\x0A\x0D\x20]+(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x3F]|\?(?!>))*)?\?>|<!--(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x2D]|-(?!-))*-->|<!DOCTYPE[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*(?:[\x09\x0A\x0D\x20]+(?:SYSTEM[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*')|PUBLIC[\x09\x0A\x0D\x20]+(?:"[\x0A\x0D\x20\x21\x23-\x25\x27-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*"|'[\x0A\x0D\x20\x21\x23-\x25\x28-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*')[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*')))?[\x09\x0A\x0D\x20]*(?:\[(?:(?:<!ELEMENT[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*[\x09\x0A\x0D\x20]+(?:EMPTY|ANY|\([\x09\x0A\x0D\x20]*#PCDATA(?:(?:[\x09\x0A\x0D\x20]*\|[\x09\x0A\x0D\x20]*[:_A-z][-.0-9:_A-z\xB7]*)*[\x09\x0A\x0D\x20]*\)\*|[\x09\x0A\x0D\x20]*\))|(?:(?P<choice>\([\x09\x0A\x0D\x20]*(?:[:_A-z][-.0-9:_A-z\xB7]*|(?P>choice)|(?P>seq))[?*+]?(?:[\x09\x0A\x0D\x20]*\|[\x09\x0A\x0D\x20]*(?:[:_A-z][-.0-9:_A-z\xB7]*|(?P>choice)|(?P>seq))[?*+]?)+[\x09\x0A\x0D\x20]*\))|(?P<seq>\([\x09\x0A\x0D\x20]*(?:[:_A-z][-.0-9:_A-z\xB7]*|(?P>choice)|(?P>seq))[?*+]?(?:[\x09\x0A\x0D\x20]*,[\x09\x0A\x0D\x20]*(?:[:_A-z][-.0-9:_A-z\xB7]*|(?P>choice)|(?P>seq))[?*+]?)*[\x09\x0A\x0D\x20]*\)))[?*+]?)[\x09\x0A\x0D\x20]*>|<!ATTLIST[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*(?:[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*[\x09\x0A\x0D\x20]+(?:CDATA|(?:ID(?:REFS?)?|ENTIT(?:Y|IES)|NMTOKENS?)|(?:NOTATION[\x09\x0A\x0D\x20]+\([\x09\x0A\x0D\x20]*[:_A-z][-.0-9:_A-z\xB7]*(?:[\x09\x0A\x0D\x20]*\|[\x09\x0A\x0D\x20]*[:_A-z][-.0-9:_A-z\xB7]*)*[\x09\x0A\x0D\x20]*\)|\([\x09\x0A\x0D\x20]*(?:[-.0-9:_A-z\xB7])+(?:[\x09\x0A\x0D\x20]*\|[\x09\x0A\x0D\x20]*(?:[-.0-9:_A-z\xB7])+)*[\x09\x0A\x0D\x20]*\)))[\x09\x0A\x0D\x20]+(?:#(?:REQUIRED|IMPLIED)|(?:#FIXED[\x09\x0A\x0D\x20]+)?(?:"(?:[^<&"]|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*"|'(?:[^<&']|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*')))*[\x09\x0A\x0D\x20]*>|(?:<!ENTITY[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*[\x09\x0A\x0D\x20]+(?:(?:"(?:[^%&"]|%[:_A-z][-.0-9:_A-z\xB7]*;|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*"|'(?:[^%&']|%[:_A-z][-.0-9:_A-z\xB7]*;|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*')|(?:SYSTEM[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*')|PUBLIC[\x09\x0A\x0D\x20]+(?:"[\x0A\x0D\x20\x21\x23-\x25\x27-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*"|'[\x0A\x0D\x20\x21\x23-\x25\x28-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*')[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*'))(?:[\x09\x0A\x0D\x20]+NDATA[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*)?)[\x09\x0A\x0D\x20]*>|<!ENTITY[\x09\x0A\x0D\x20]+%[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*[\x09\x0A\x0D\x20]+(?:(?:"(?:[^%&"]|%[:_A-z][-.0-9:_A-z\xB7]*;|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*"|'(?:[^%&']|%[:_A-z][-.0-9:_A-z\xB7]*;|&(?:[:_A-z][-.0-9:_A-z\xB7]*|#(?:[0-9]+|x[0-9a-fA-F]+));)*')|(?:SYSTEM[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*')|PUBLIC[\x09\x0A\x0D\x20]+(?:"[\x0A\x0D\x20\x21\x23-\x25\x27-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*"|'[\x0A\x0D\x20\x21\x23-\x25\x28-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*')[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*')))[\x09\x0A\x0D\x20]*>)|<!NOTATION[\x09\x0A\x0D\x20]+[:_A-z][-.0-9:_A-z\xB7]*[\x09\x0A\x0D\x20]+(?:(?:SYSTEM[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*')|PUBLIC[\x09\x0A\x0D\x20]+(?:"[\x0A\x0D\x20\x21\x23-\x25\x27-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*"|'[\x0A\x0D\x20\x21\x23-\x25\x28-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*')[\x09\x0A\x0D\x20]+(?:"[^"]*"|'[^']*'))|PUBLIC[\x09\x0A\x0D\x20]+(?:"[\x0A\x0D\x20\x21\x23-\x25\x27-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*"|'[\x0A\x0D\x20\x21\x23-\x25\x28-\x2F\x3A\x3B\x3D\x3F\x40_0-9A-z]*'))[\x09\x0A\x0D\x20]*>|<\?[:_A-z][-.0-9:_A-z\xB7]*(?<!(?i:\?xml))(?:[\x09\x0A\x0D\x20]+(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x3F]|\?(?!>))*)?\?>|<!--(?:[^\x01-\x08\x0B\x0C\x0E-\x1F\x2D]|-(?!-))*-->)|(?:%[:_A-z][-.0-9:_A-z\xB7]*;|[\x09\x0A\x0D\x20]+))*][\x09\x0A\x0D\x20]*)?>"## let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines) let testString = #""" <appointments> <event date="03-05-02" start-time="09:00" end-time="10:00"> <type>Meeting</type> <title>Staff Meeting</title> <description>Weekly staff meeting</description> <location>Conference Room</location> <reminder status="no"/> </event> <event date="03-06-02" start-time="14:00" end-time="15:00"> <type>Interview</type> <title>Developer Interview</title> <description>Interview new developer candidate.</description> <location>Office</location> <reminder status="yes" interval="15-min" method="ICQ"/> </event> <event date="03-15-02" start-time="13:45" end-time="15:00"> <type>Dentist</type> <title>Root Canal</title> <description>Root canal on lower left molar.</description> <location>Dr. Scrivello's Office</location> <reminder status="yes" interval="1-day" method="e-mail"/> </event> </appointments> """# let stringRange = NSRange(location: 0, length: testString.utf16.count) let matches = regex.matches(in: testString, range: stringRange) var result: [[String]] = [] for match in matches { var groups: [String] = [] for rangeIndex in 1 ..< match.numberOfRanges { let nsRange = match.range(at: rangeIndex) guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue } let string = (testString as NSString).substring(with: nsRange) groups.append(string) } if !groups.isEmpty { result.append(groups) } } print(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 Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression