iOS 分词

func wordBoundary(_ text: String) -> [String] {
        let tokenize = CFStringTokenizerCreate(kCFAllocatorDefault, text as CFString?, CFRangeMake(0, text.count), kCFStringTokenizerUnitWordBoundary, CFLocaleCopyCurrent())
        CFStringTokenizerAdvanceToNextToken(tokenize)
        var range = CFStringTokenizerGetCurrentTokenRange(tokenize)
        var boundaries : [String] = []
        while range.length > 0 {
            let wRange = text.index(text.startIndex, offsetBy: range.location)..<text.index(text.startIndex, offsetBy: range.location + range.length)
            let keyWord = String(text[wRange])
            boundaries.append(keyWord)
            CFStringTokenizerAdvanceToNextToken(tokenize)
            range = CFStringTokenizerGetCurrentTokenRange(tokenize)
        }
        return boundaries
    }
    
func wordBoundariesWithSentences(_ text: String) -> [Dictionary<String, Array<String>>] {
        let tokenize = CFStringTokenizerCreate(kCFAllocatorDefault, text as CFString?, CFRangeMake(0, text.count), kCFStringTokenizerUnitSentence, CFLocaleCopyCurrent())
        CFStringTokenizerAdvanceToNextToken(tokenize)
        var range = CFStringTokenizerGetCurrentTokenRange(tokenize)
        var result : [Dictionary<String, Array<String>>] = []
        while range.length > 0 {
            let wRange = text.index(text.startIndex, offsetBy: range.location)..<text.index(text.startIndex, offsetBy: range.location + range.length)
            let sentence = String(text[wRange])
            let words = wordBoundary(sentence)
            result.append([sentence: words])
            CFStringTokenizerAdvanceToNextToken(tokenize)
            range = CFStringTokenizerGetCurrentTokenRange(tokenize)
        }
        return result
    }