Question

我需要检测从pdf文件读取的字符串的语言，该文本基本上是英语，但“ NLLanguageRecognizer”返回的是“罗马尼亚语”

我正在使用的功能是：

 class func detectedLangaugeFormat(for string: String) -> String {
       if #available(iOS 12.0, *) {
           let recognizer = NLLanguageRecognizer()
           recognizer.processString(string)
        guard let languageCode = recognizer.dominantLanguage?.rawValue else { return "rtl" }
           let detectedLangauge = Locale.current.localizedString(forIdentifier: languageCode)
           print("lan")
           let currentLocale = NSLocale.current as NSLocale
           let direction: NSLocale.LanguageDirection = NSLocale.characterDirection(forLanguage: languageCode)
            if direction == .rightToLeft {
                return "rtl"
            }else if direction == .leftToRight {
                return "ltr"
            }
       } else {
           // Fallback on earlier versions
       }


    return "rtl"
   }

，为此方法提供的字符串是：

"\r\n                A Simple PDF File \r\n                   This is a small demonstration .pdf file - \r\n                   just for use in the Virtual Mechanics tutorials. More text. And more \r\n                   text. And more text. And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. And more text. Boring, zzzzz. And more text. And more text. And \r\n                   more text. And more text. And more text. And more text. And more text. \r\n                   And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. And more text. And more text. Even more. Continued on page 2 ...\r\n                Simple PDF File 2 \r\n                   ...continued from page 1. Yet more text. And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. Oh, how boring typing this stuff. But not as boring as watching \r\n                   paint dry. And more text. And more text. And more text. And more text. \r\n                   Boring.  More, a little more text. The end, and just as well. "

Answer 1

一种可能的解决方案是删除字符串中多个空格。

let regex = try? NSRegularExpression(pattern: "  +", options: .caseInsensitive)
    str = regex?.stringByReplacingMatches(in: str, options: [], range: NSRange(location: 0, length: str.count), withTemplate: " ") ?? ""

我使用此正则表达式尝试了您的字符串，并且该字符串有效。语言识别器返回了英语代码。

Answer 2

由于某些原因，空格和换行符会使processString(_:)的结果无效。您应该做的是在将字符串传递给您的方法之前摆脱它们：

let givenString = "\r\n                A Simple PDF File \r\n                   This is a small demonstration .pdf file - \r\n                   just for use in the Virtual Mechanics tutorials. More text. And more \r\n                   text. And more text. And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. And more text. Boring, zzzzz. And more text. And more text. And \r\n                   more text. And more text. And more text. And more text. And more text. \r\n                   And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. And more text. And more text. Even more. Continued on page 2 ...\r\n                Simple PDF File 2 \r\n                   ...continued from page 1. Yet more text. And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. Oh, how boring typing this stuff. But not as boring as watching \r\n                   paint dry. And more text. And more text. And more text. And more text. \r\n                   Boring.  More, a little more text. The end, and just as well. "
let trimmedString = givenString.trimmingCharacters(in: .whitespacesAndNewlines)

let result = detectedLangaugeFormat(for: trimmedString)
print(result) // ltr

这时，它应该可以识别为英文（如果在方法中打印detectedLangauge而不是“ lan”，则会发现它是“英文”）。

let detectedLangauge = Locale.current.localizedString(forIdentifier: languageCode)
print(detectedLangauge) // Optional("English")

Answer 3

删除字符串中的非字母[WhiteSpaces，！，@，＃等] char，然后尝试检测语言。

extension String{
    func findFirstAlphabetic() -> String.Index?{
        for index  in self.indices{
            if String(self[index]).isAlphanumeric == true{
                return index
            }
        }
        return nil
    }
    var isAlphanumeric: Bool {
        return !isEmpty && range(of: "[^a-zA-Z0-9]", options: .regularExpression) == nil
    }
    func alphabetic_Leading_SubString() -> String?{
        if let startIndex =  self.findFirstAlphabetic(){
            let newSubString = self[startIndex..<self.endIndex]
            return String(newSubString)
        }
        return nil
    }
}

用法：-

let string = "\r\n                A Simple PDF File \r\n                   This is a small demonstration .pdf file - \r\n                   just for use in the Virtual Mechanics tutorials. More text. And more \r\n                   text. And more text. And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. And more text. Boring, zzzzz. And more text. And more text. And \r\n                   more text. And more text. And more text. And more text. And more text. \r\n                   And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. And more text. And more text. Even more. Continued on page 2 ...\r\n                Simple PDF File 2 \r\n                   ...continued from page 1. Yet more text. And more text. And more text. \r\n                   And more text. And more text. And more text. And more text. And more \r\n                   text. Oh, how boring typing this stuff. But not as boring as watching \r\n                   paint dry. And more text. And more text. And more text. And more text. \r\n                   Boring.  More, a little more text. The end, and just as well. "
detectedLangaugeFormat(for: string.alphabetic_Leading_SubString()!)

检测字符串的语言

3 个答案: