import Foundation
let pattern = #"(?P<startDay>\d{2})\s(?P<finishDay>\d{2})\sdel?\s(?P<month>\d{2})\sdel?\s(?P<year>\d+)"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = ##"""
05 del 07 del 2000 del 09 hhggh" #example 0 - Not modify!
04 del 05 del 07 del 2000" #example 1 - Not modify!
04 05 del 06 de 200" #example 2 - Yes modify!
04 05 del 06 de 20076 55" #example 3 - Yes modify!
"""##
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"\g<startDay> \g<finishDay>-\g<month>-\g<year>"#
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