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

Generated Code

import Foundation let pattern = #"^\[Error: +(?<source_path>(?<file>[^\s\n](?:[^\n:\\]+|\\.)+?)(?::(?<line>\d+)(?::(?<column>\d+)))?) *$"# let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines) let testString = #""" /usr/local/lib/node_modules/stylus/bin/stylus:685 throw err; ^ [Error: /Users/user/path/to/stylus/file/invalid.styl:34:5 30| ==/UserStyle== */ 31| 32| @-moz-document regexp("https?://(www\\.)?typescriptlang.org/(v2/)?docs.*$"), 33| regexp("https?://(www\\.)?(staging-)?typescript\\.org/docs/.*$") 34| error("compile error") -----------^ 35| compile error ] { fromStylus: true, lineno: 34, column: 5, filename: '/Users/disk0/git.local/stylus-stylus/static/test/testFiles/invalid.styl', stylusStack: '', input: '/* ==UserStyle==\n' + '@name TypeScript Docs\n' + '@description Expands width of code blocks and moves navigation bar fully to the left\n' + '@version 0.0.12\n' + '@namespace github.com/disk0/stylus/typescript.org/docs\n' + '\n' + '@author disk0 (github.com/disco0)\n' + '@license MIT\n' + '\n' + '@preprocessor stylus\n' + '\n' + '@var select CodeFont "Font for code displayed on page." [\n' + ' "Iosevka Extended*",\n' + ' "Iosevka Expanded",\n' + ' "Iosevka Term",\n' + ' "Iosevka",\n' + '\n' + ' "SemanticHaskell",\n' + ' "SemanticJavascript",\n' + ' "SemanticCode",\n' + ' "Hasklig",\n' + '\n' + ' "PragmataPro Mono Liga",\n' + '\n' + ' "monospace"\n' + ']\n' + '@var number CodeFontSize "Size of code in documentation" [ 14, 1, 500, 1, "px" ]\n' + '@var number CodeFontWeight "Code font weight" [ 400, 100, 900, 100 ]\n' + '@var number DocTextWidth "Width of text content in documentation" [ 1000, 300, 5000, 100, "px" ]\n' + '==/UserStyle== */\n' + '\n' + '@-moz-document regexp("https?://(www\\\\.)?typescriptlang.org/(v2/)?docs.*$"),\n' + '\t regexp("https?://(www\\\\.)?(staging-)?typescript\\\\.org/docs/.*$")\n' + ' error("compile error")\n' } """# 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