import Foundation
let pattern = #"^\+?1-?\(?(\d{3})\)?[- ]?(\d{3})\-?(\d{4})$"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
19999999999
+19999999999
1-999-999-9999
1-(999) 999-9999
1238934265981239
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"1($1) $2-$3"#
let result = regex.stringByReplacingMatches(in: testString, range: stringRange, withTemplate: substitutionString)
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