import Foundation
let pattern = #"""
A\s+change\s+to\s+
(?:(?:sub)?headings?|tariff\s+item)
\s+\d[0-9.]*
(?:\s+through\s+\d[0-9.]*)?
\s+from(?:(?:,?\s+(?:sub)?headings?\s+\d[0-9.]*)+(?:\s+or\s+\d[0-9.]*)*\s+or)?
\s+any\s+other\s+(?:heading|chapter)\.
"""#
let regex = try! NSRegularExpression(pattern: pattern, options: [.anchorsMatchLines, .allowCommentsAndWhitespace])
let testString = #"""
A change to headings 0101 through 0106 from any other chapter.
A change to subheadings 0712.20 through 0712.39 from any other chapter.
A change to heading 0903 from any other chapter.
A change to subheading 1806.20 from any other heading.
A change to subheading 1207.99 from any other chapter.
A change to heading 4302 from any other heading.
A change to subheading 4105.10 from heading 4102 or any other chapter.
A change to subheading 4105.30 from heading 4102, subheading 4105.10 or any other chapter.
A change to subheading 4106.21 from subheading 4103.10 or any other chapter.
A change to subheading 4106.22 from subheadings 4103.10 or 4106.21 or any other chapter.
A change to tariff item 7304.41.30 from subheading 7304.49 or any other chapter.
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let matches = regex.matches(in: testString, range: stringRange)
var result: [[String]] = []
for match in matches {
var groups: [String] = []
for rangeIndex in 1 ..< match.numberOfRanges {
let nsRange = match.range(at: rangeIndex)
guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue }
let string = (testString as NSString).substring(with: nsRange)
groups.append(string)
}
if !groups.isEmpty {
result.append(groups)
}
}
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