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"
"
g

Test String

Code Generator

Generated Code

import Foundation let pattern = #"(?<=src=\\").*?(?=\\")"# let regex = try! NSRegularExpression(pattern: pattern) let testString = #"{"Items":[{"ItemID":10198,"ItemType":null,"Subject":null,"SubjectID":14,"Area":null,"AreaID":18,"Topic":null,"TopicID":18,"SubTopicID":0,"ItemBankName":null,"Direction":"","ItemTitle":"Q.53","IsApproved":false,"Item":"\u003cp\u003e\u003cspan style=\"font-size: 14.7px;\"\u003eThe\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e efficiency of the screw\u0026nbsp;\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003ein %\u0026nbsp;\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003eupto\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e two decimal places is\u0026nbsp;\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e[quizky-text]\u003c/span\u003e\u003c/p\u003e","ItemPassageID":352,"Passage":"\u003cp\u003e\u003cstrong\u003e\u003cspan style=\"font-size: 14.7px;\"\u003eStatement\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e for Linked Answer Questions 52 and 53:\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003cbr /\u003e \u003cspan style=\"font-size: 14.7px;\"\u003eA load of 30 KN is raised by means of a screw jack having square threaded screw of pitch 12 mm. The spindle diameter is 50 mm. If a force of 350 N is applied at the end of a lever to raise the load, co-efficient of friction\u0026nbsp;\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003eis\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e 0.15.\u003c/span\u003e\u003c/p\u003e","PassageTitle":null,"IsLinkedQuestion":false,"Points":0,"Explanation":"\u003cp\u003e\u003cspan style=\"font-family: Symbol;\"\u003eh\u003c/span\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e =\u0026nbsp;\u003c/span\u003e\u003cimg style=\"vertical-align: bottom;\" src=\"QUIZKYIMAGEREPO/docximg_1128711867_image197.png\" alt=\"\" width=\"54\" height=\"32\" data-docx-image=\"image197.emf\" /\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e =\u0026nbsp;\u003c/span\u003e\u003cimg style=\"vertical-align: bottom;\" src=\"QUIZKYIMAGEREPO/docximg_1128711867_image198.png\" alt=\"\" width=\"40\" height=\"31\" data-docx-image=\"image198.emf\" /\u003e\u003cspan style=\"font-size: 14.7px;\"\u003e = 33%\u003c/span\u003e\u003c/p\u003e","ItemBankID":0,"LOD":null,"LODID":2,"ItemBank":0,"QuestionPaper":0,"IsProofRead":false,"CorrectIndex":0,"QuestionPaperSectionID":0,"ItemOptionModel":null}],"ItemOptions":[{"ItemOptionID":37637,"ItemID":0,"Option":"\u003cp\u003e\u003cspan style=\"font-family: Arial; font-size: 12px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003cspan style=\"font-family: Arial; font-size: 12px;\"\u003e33.36\u003c/span\u003e\u003c/p\u003e","RHSOption":null,"MarkedIndex":null,"OrderNumber":null,"OptionIndex":0,"IsCorrect":false,"IsHTML":false,"RHSIsHTML":false,"ColumnID":0},{"ItemOptionID":37638,"ItemID":0,"Option":"\u003cp\u003e\u003cspan style=\"font-family: Arial; font-size: 12px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003cspan style=\"font-family: Arial; font-size: 12px;\"\u003e33.36\u003c/span\u003e\u003c/p\u003e","RHSOption":null,"MarkedIndex":null,"OrderNumber":null,"OptionIndex":0,"IsCorrect":false,"IsHTML":false,"RHSIsHTML":false,"ColumnID":0}]}"# 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