import Foundation
let pattern = #"(?<result>(?<data>^[\d|,]+)(?: in )(?<cat>.+?)(?<extra>\s+(?:\(.+?\)?)?))$"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
286,879 in Home & Kitchen (See Top 100 in Home & Kitchen)
339 in Cardboard Cutouts
2,945 in Jigsaws (Toys & Games)
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let substitutionString = #"$3 = $2"#
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