Swift. How to delete the character at the beginning and end of the string?

Question

It is necessary to remove the quotes at the beginning and end of the line, if they are in the line Could it be more beautiful?

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

If you like a one liner:

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

---

You could define these extensions to make it look a tad prettier:

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

And use it like so:

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

---

If you only need to remove the first and last quotes, if they are both present, then I would only add a check that the count is at least 2 characters, since a string like "\"" has quotes in both the prefix and suffix, but it's not between quotes:

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

and use it like so:

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

Answer 2

You can use Collection removeFirst and removeLast mutating methods:

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

you can do so:

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

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