Question

如果行中有引号，则必须删除它们会更美丽吗？

var str = "\"Hello, playground\""
let quotes = "\""

if str.hasPrefix(quotes) && str.hasSuffix(quotes) {
    let v = str.dropFirst()
    str = String(v.dropLast())
}
print(str)

Answer 1

如果您喜欢一个班轮：

let str = "\"\"\"Hello, playground\"\""
let unquoted = String(str.drop(while: { $0 == "\""}).reversed().drop(while: { $0 == "\""}).reversed())
print(unquoted)  //Hello, playground

您可以定义这些扩展名，使其看起来更漂亮：

extension String {
    private func removeQuotesAndReverse() -> String {
        return String(self.drop(while: { $0 == "\""}).reversed())
    }
    func unquote() -> String {
        return self.removeQuotesAndReverse().removeQuotesAndReverse()
    }
}

并像这样使用它：

let unquoted = "\"\"\"Hello, playground\"\"".unquote()

如果只需要删除第一个和最后一个引号（如果它们都存在），那么我将只添加一个检查，以确保计数至少为2个字符，因为像"\""这样的字符串都包含引号前缀和后缀，但不在引号之间：

extension String {
    func withoutDoubleQuotes() -> String {
        if self.hasPrefix("\""), self.hasSuffix("\""), self.count > 1 {
            return String(self.dropFirst().dropLast())
        }
        return self
    }
}

并像这样使用它：

"\"Hello, playground\"".withoutDoubleQuotes()       //Hello, playground
"\"\"\"Hello, playground\"\"".withoutDoubleQuotes() //""Hello, playground"
"\"".withoutDoubleQuotes()                          //"
"\"\"".withoutDoubleQuotes()                        //

Answer 2

您可以使用Collection removeFirst和removeLast变异方法：

var str = "\"Hello, playground\""
let quotes = "\""

if str.hasPrefix(quotes) && str.hasSuffix(quotes) && str != quotes {
    str.removeFirst()
    str.removeLast()
}
print(str)  // "Hello, playground\n"

Answer 3

您可以这样做：

let str = "\"Hello, playground\""

let new = str.filter{$0 != "\""}

迅速。如何删除字符串开头和结尾的字符？

3 个答案: