NSRegularExpressionsExamples.swift

//: These Swift examples follow the Objective-C found in [NSRegularExpression](https://developer.apple.com/documentation/foundation/nsregularexpression)

import Foundation

let regex1 = try! NSRegularExpression(pattern: "\\b(a|b)(c|d)\\b", options: [.caseInsensitive])

let string1 = "Test with Ad and ad and Ac and AC and bD and bd and Bc and BC in the string."

let range1 = NSMakeRange(0, string1.count)

let numberOfMatches = regex1.numberOfMatches(in: string1, range: range1)

let firstRange = regex1.rangeOfFirstMatch(in: string1, range: range1)

let matchResults = regex1.matches(in: string1, range: range1)
for (index, matchResult) in matchResults.enumerated() {
  print(index, matchResult.range, NSString(string: string1).substring(with: matchResult.range))
}

let firstResult = regex1.firstMatch(in: string1, range: range1)!
print(firstResult.range, NSString(string: string1).substring(with: firstResult.range))

regex1.enumerateMatches(
  in: string1, options: [], range: range1,
  using: { result, flags, stop
    in
    // The NSTextCheckingResult is always non-nil given options of [].
    guard let result = result else { return }
    print(result.range, NSString(string: string1).substring(with: result.range))
})

print(regex1.stringByReplacingMatches(in: string1, range: range1, withTemplate: "$2$1"))

let mutableString1 = NSMutableString(string: string1)

regex1.replaceMatches(in: mutableString1, range: range1, withTemplate: "$2$1")
print(mutableString1)