import Foundation
let pattern = #"(<span class='customer)(' id='phone\$1[^>]*>)([^<]+)"#
let regex = try! NSRegularExpression(pattern: pattern)
let testString = #"""
GIVEN:
<div>
<span class='customer' id='phone$0'>Home</span>
<br/>
<span class='customer' id='phone$1'>Business</span>
<br/>
<span class='customer' id='phone$2'>Mobile</span>
</div>
DESIRED:
<span class='customer NewClass' id='phone$1'>Organization</span>
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"$1 NewClass$2Organization"#
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