import Foundation
let pattern = #"\.zip\b[^,]*(*SKIP)(*F)|\s"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
http://abcd.com/old file/anotherfile.zip/some contents/sample.txt,http://abcd.com/new file/anotherfile.zip/some more contents/new sample.txt,http://abcd.com/newer file/another file.zip/some more contents/old sample.txt,http://abcd.com/newer file/another file.txt
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"%20"#
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