import Foundation
let pattern = #"(.*?): (.*)"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
Matthäuspassion, SWV 479: Introitus:Test
Matthäuspassion, SWV 479:Introitus:Test
letztlich
Matthäuspassion, SWV 479: Introitus - Test
Erster Text, zweiter Text : Dritter Text
Vierter Text, fünfter Text : Sechster Text
Siebter Text, achter Text : Neunter Text
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"$1 xxx $2"#
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