Question

如何在保留分隔字符串的同时将字符串拆分为数组？

您可以这样做来拆分字符串，但不会保留分隔符的子字符串：

“我的名字” .components（separatedBy：“-”）-> [“我的”，“名字”]

这是我要实现的目标：

例1：“我的名字” .someSplitFunc（separatedBy：“-”）-> [“我的”，“名字”]

例2：“这是一个句子”。someSplitFunc（separatedBy：“-”）-> [“ This-”， “是-”，“ a-”，“句子”]

Answer 1

您可以尝试以下方法：

var str = "This-is-a-sentence"
var separateList = str.components(separatedBy: "-")
for (index, _) in separateList.enumerated() {
    if index < separateList.count - 1 {
        separateList[index].append("-")
    }
}

print(separateList)

Answer 2

AFAIK没有本机Swift方法可以完成您想要的操作。您将需要实现扩展Collection的自己的split方法。像这样：

extension Collection {
    func splitAndKeep(separator: Element, maxSplits: Int = .max, omittingEmptySubsequences: Bool = true) -> [SubSequence] where Element: Equatable {
        splitAndKeep(maxSplits: maxSplits, omittingEmptySubsequences: omittingEmptySubsequences) { $0 == separator }
    }
    func splitAndKeep(maxSplits: Int = .max, omittingEmptySubsequences: Bool = true, whereSeparator isSeparator: (Element) throws -> Bool) rethrows -> [SubSequence] {
        guard !isEmpty else { return [] }
        let positions = try indices.filter { try isSeparator(self[$0]) }
        var subSequences: [SubSequence] = []
        var start = startIndex
        for position in positions {
            let subsequence = self[start...position]
            if !subsequence.isEmpty {
                subSequences.append(subsequence)
                if subSequences.count == maxSplits {
                    return subSequences
                }
            }
            start = index(after: position)
        }
        let tail = self[start...]
        if subSequences.count < maxSplits, !omittingEmptySubsequences || !tail.isEmpty {
            subSequences += CollectionOfOne(tail)
        }
        return subSequences
    }
}

let string = "This-is-a-sentence"
string.splitAndKeep(separator: "-")  // ["This-", "is-", "a-", "sentence"]

let str2 = "This is a sentence, and this is another one. Hello World!"
let subsequences = str2.splitAndKeep(whereSeparator: \.isPunctuation)   // ["This is a sentence,", " and this is another one.", " Hello World!"]
let firstSentence = str2.splitAndKeep(maxSplits: 1, whereSeparator: \.isPunctuation)   // ["This is a sentence,"]

Answer 3

只需在下面使用此扩展名即可。

extension String {
    func componentSeparate(by: String) -> [String] {
        var out: [String] = [String]()
        var storeStr = ""
        for str in Array(self) {
            if by.contains(str) {
                out.append(storeStr)
                storeStr.removeAll()
                continue
            }
            storeStr.append(str)
        }
        return out
    }
    
    func componentSeparated1(by: String) -> [String] {
        var separateList: [String] = componentSeparate(by: by).map { "\($0)\(by)" }
        separateList[separateList.count-1].removeLast(by.count)
        return separateList
    }
    
    func componentSeparated2(by: String) -> [String] {
        if self.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty { return [] }
        var separateList: [String] = componentSeparate(by: by).map { "\($0)\(by)" }
        separateList[separateList.count-1].removeLast(by.count)
        return separateList
    }
    
    func componentSeparated3(by: String) -> [String] {
        if self.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty { return [] }
        var separateList: [String] = componentSeparate(by: by).map {"\($0)\(by)"}.filter {$0 != "-"}
        separateList[separateList.count-1].removeLast(by.count)
        return separateList
    }
    
    func componentSeparated4(by: String) -> [String] {
        if self.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty { return [] }
        let separateList: [String] = componentSeparate(by: by).map {"\($0)\(by)"}.filter {$0 != "-"}
        return separateList
    }
}

print("This-is-a-sentence-".componentSeparated1(by: "-"))
print("".componentSeparated2(by: "-"))
print("This-is-a-sentence-".componentSeparated3(by: "-"))
print("This-is-a-sentence-".componentSeparated4(by: "-"))

输出：

["This-", "is-", "a-", "sentence-", ""]
[]
["This-", "is-", "a-", "sentence"]
["This-", "is-", "a-", "sentence-"]

在Swift中拆分字符串，同时保留拆分字符串

3 个答案: