您可以使用String方法enumerateSubstringsInRange。第一个参数只是传递您的字符串Range<Index>和选项.byWords。只需将每个子字符串附加到结果集合中并返回即可。
（对于较早的Swift语法，请检查编辑历史记录）
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"]
清洁标点符号过滤字符串中的字母和空格
let clean = sentence.filter{ $0.isLetter || $0.isWhitespace }
查找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"
}
查找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""
}
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