Swift：如何识别和删除字符串中的介词

Question

我试图在用户条目中识别要搜索的关键字，所以我想过滤掉一些词性以便提取要在我的数据库中查询的关键字。目前我使用下面的代码替换字符串中的单词“of”

 let rawString = "I’m jealous of my parents. I’ll never have a kid as cool as theirs, one who is smart, has devilishly good looks, and knows all sorts of funny phrases."

 var filtered = self.rawString.replacingOccurrences(of: "of", with: "")

我现在想做的是扩展它以替换字符串中的所有介词。

我想做的是创建一个巨大的已知介词列表，例如

 let prepositions = ["in","through","after","under","beneath","before"......]

然后用白色 space 和

分割字符串

var WordList : [String] = filtered.components(separatedBy: " ")

然后遍历单词列表以找到介词匹配并将其删除。创建列表会很丑陋，而且对我的代码来说可能效率不高。

从字符串中检测和删除介词的最佳方法是什么？

Answer 1

var newString = rawString
    .split(separator: " ")
    .filter{ !prepositions.contains(String([=10=]))}
    .joined(separator: " ")

Answer 2

使用NaturalLanguage:

import NaturalLanguage

let text = "The ripe taste of cheese improves with age."
let tagger = NLTagger(tagSchemes: [.lexicalClass])
tagger.string = text
let options: NLTagger.Options = [.omitPunctuation, .omitWhitespace]

var newSentence = [String]()

tagger.enumerateTags(in: text.startIndex..<text.endIndex, unit: .word, scheme: .lexicalClass, options: options) { tag, tokenRange in
    guard let tag = tag, tag != .preposition else { return true }
    newSentence.append("\(text[tokenRange])")
    return true
}

print("Input: \(text)")
print("Output: \(newSentence.joined(separator: " "))")

这会打印：

Input: The ripe taste of cheese improves with age.
Output: The ripe taste cheese improves age

注意两个介词 of 和 with 被删除了。我的方法还删除了标点符号；您可以使用 .omitPunctuation 选项进行调整。

Swift：如何识别和删除字符串中的介词

Swift: How to identify and delete prepositions in a string

swift

string-matching