import Foundation
let pattern = #"(/sites(?:/[^/\"]+){2}/SitePages/[^/\"]+)\.aspx(?=\")"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"<div class="ms-wikicontent ms-rtestate-field" style="padding-right: 10px"><div class="ExternalClass8E56354CC4314DBA861E187B689F3A2B"><table id="layoutsTable" style="width:100%"><tbody><tr style="vertical-align:top"><td style="width:100%"><div class="ms-rte-layoutszone-outer" style="width:100%"><div class="ms-rte-layoutszone-inner" role="textbox" aria-haspopup="true" aria-autocomplete="both" aria-multiline="true"><a id="0::Home|Home" class="ms-wikilink" href="/sites/Team/Project/SitePages/Home.aspx">Home</a> - <a id="1::Jenkins|Jenkins" class="ms-wikilink" href="/sites/Team/Project/SitePages/Jenkins.aspx">Jenkins</a><h1 class="ms-rteElement-H1">Jenkins Integration with Deployment Tools</h1>"#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"$1.html"#
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