import Foundation
let pattern = #"(?:(?<=\.(?:com|cn)(\:\d+(?!\d)))|(?<=\.(?:com|cn)(?!:\d+|\.)))(?!\/)"#
let regex = try! NSRegularExpression(pattern: pattern)
let testString = #"""
https://live-rv.duizhuang.com:123aaa/bb
https://live-rv.duizhuang.com:123/aaa/bb
https://live-rv.duizhuang.com/aaa/bb
https://live-rv.duizhuang.cn2/aaa/bb
https://img.dz8.cn/2/aaa/bb.png!/1/1
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"/"#
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