import Foundation
let pattern = #"\b(first|second|third|fourth)(?=(?:\s*(?:,|and)\s*(?:first|second|third|fourth))*\s+section\b)"#
let regex = try! NSRegularExpression(pattern: pattern)
let testString = #"""
1. something first, other and then second, third and fourth section
2. something first and other and then second, third and fourth section
3. something first, second other and then second, third and fourth section
4. fourth section
5. something first, second, third and fourth section
"""#
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