Question

在Swift中提取String中的最后一个单词的方法是什么？因此，如果我有一个Lorem ipsum dolor坐下来，那就回复＆＃34; amet＆＃34;。这样做最有效的方法是什么？

Answer 1

您可以使用String方法enumerateSubstringsInRange。第一个参数只传递字符串Range<Index>和选项.byWords。只需将每个子字符串附加到生成的集合中并将其返回。

Swift 5或更高版本（对于较旧的Swift语法检查编辑历史记录）

import Foundation

extension StringProtocol { // for Swift 4 you need to add the constrain `where Index == String.Index` 
    var byWords: [SubSequence] {
        var byWords: [SubSequence] = []
        enumerateSubstrings(in: startIndex..., options: .byWords) { _, range, _, _ in
            byWords.append(self[range])
        }
        return byWords
    }
}

用法：

let sentence = "Out of this world!!!"
let words = sentence.byWords             // ["Out", "of", "this", "world"]
let firstWord = words.first      // "Out"
let lastWord = words.last         // world"
let first2Words = words.prefix(2) // ["Out", "of"]
let last2Words = words.suffix(2)   // ["this", "world"]

没有导入基础

清除过滤字符串的字母和空格的标点字符

let clean = sentence.filter{ $0.isLetter || $0.isWhitespace }

找到字符串中最后一个空格的索引

if let index = clean.lastIndex(of: " ") {
    let lastWord = clean[index...]
    print(lastWord)   // "world"
}

找到字符串中第一个空格的索引

if let index = clean.firstIndex(of: " ") {
    let firstWord = clean[...index]
    print(firstWord)  // "Out""
}

Answer 2

如果您想要包含基础课程，其他答案都可以。如果你想使用仅限Swift的类，那么你可以这样做：

一种方法是使用索引。这可能是使用长字符串的最快方法：

斯威夫特4：

I am a student.<ctrl-z>

或者您可以分割字符串：

斯威夫特4：

let str = "Lorem ipsum dolor sit amet"
let size = str.reversed().firstIndex(of: " ") ?? str.count
let startWord = str.index(str.endIndex, offsetBy: -size)
let last = str[startWord...] // -> "amet"

斯威夫特3：

let str = "Lorem ipsum dolor sit amet"
let split = str.split(separator: " ")
let last    = String(split.suffix(1).joined(separator: [" "]))
let lastTwo = String(split.suffix(2).joined(separator: [" "]))

print(last)    // -> "amet"
print(lastTwo) // -> "sit amet”

斯威夫特2：

let str = "Lorem ipsum dolor sit amet"
let split = str.characters.split(separator: " ")
let last    = String(split.suffix(1).joined(separator: [" "]))
let lastTwo = String(split.suffix(2).joined(separator: [" "]))

print(last)    // -> "amet"
print(lastTwo) // -> "sit amet”

Answer 3

我还会考虑使用componentsSeparatedByCharactersInSet，并使用空白字符集：

let string = "Lorem ipsum dolor sit amet"
let stringArray = string.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
print(stringArray.last)

Answer 4

首先使用componentsSeparatedByString按空格将字符串拆分为数组，然后使用.last

获取数组的最后一个字

var string = "Lorem ipsum dolor sit amet"
var stringArr = string.componentsSeparatedByString(" ")

var lastWord = stringArr.last //amet

Answer 5

“ @ Leo Dabus”的相同解决方案，但没有切分：（Swift 4.x）

    let fullName = "Williams Diaz Robert"
    let words = fullName.components(separatedBy: " ")
    if(words.count < 2) {
        return
    }
    let fistName = String(words.last ?? "") //Robert
    let lastNameArray = words.prefix(words.count - 1)   //["Williams","Diaz"]: [String]
    let lastName = lastNameArray.joined(separator: " ") // "Williams Diaz"

Answer 6

雨燕5

extension String {

    func trim(_ emptyToNil: Bool = true)->String? {
        let text = self.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
        return emptyToNil && text.isEmpty ? nil : text
    }

    var lastWord: String? {
        if let size = self.lastIndex(of: " "), size >= self.startIndex {
            return String(self[size...]).trim()
        }
        return nil
    }

}

用法

print("Out of this world!!!".lastWord ?? "") // world!!!

Answer 7

let  value = "Hello, I am a String"
let stringArray = value.components(separatedBy: .whitespaces)
let lastWord = stringArray.last ?? ""
print(lastWord)

使用Swift提取字符串中的最后一个单词

7 个答案: