import Foundation
let pattern = #"<a ?.*? href="(?:(?:.*?example\.com.*?)|(?:[^\.]*?))".*?>(.*?)<\/a>"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
<a href="https://example.com/page_url" data-some-id="" data-other-prop="">Link 1</a>
<a data-href="" href="http://Go to page" data-another-id="">Link 2</a>
<a data-other="" href="/Go to page" data-val-id="">Link 3</a>
<a href="http://example123.com/page" data-props-id="">Link 4</a>
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"$1"#
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