matchesForRegexInText.swift

class func matchesForRegexInText(regex: String!, text: String!, captureGroupIndices:[Int]) -> [[String]] {
    do {
        let regex = try NSRegularExpression(pattern: regex, options: [.CaseInsensitive])
        let nsString = text as NSString
        let results = regex.matchesInString(text, options: [], range: NSMakeRange(0, nsString.length))
        
        return results.map { (textCheckingResult:NSTextCheckingResult) -> [String] in
            var returnValue = [String]()
            returnValue.append(nsString.substringWithRange(textCheckingResult.range))
            if textCheckingResult.numberOfRanges != captureGroupIndices.count + 1 {
                return returnValue
            }
            for captureGroupIndex in captureGroupIndices {
                returnValue.append(nsString.substringWithRange(textCheckingResult.rangeAtIndex(captureGroupIndex)))
            }
            return returnValue
        }
    } catch _ {
        assert(false, "Invalid regular expression: \(regex)")
    }
    return []
}