如何在Swift3中将ASCII转换为十六进制？

Question

I have converted the string "UK" into hex using code below. How can I convert it to hex?

    let str = auxText
    let bytes = str.utf8
    var buffer = [UInt8](bytes)
    buffer[0] = buffer[0] + UInt8(1)
    print("ascii value is",buffer)

Answer 1

In Swift 4, you can convert your ascii encoded string to data with

string.data(using: .ascii)

To convert the data to hex or decimal you can use the following extensions:

extension Data {

    var hexString: String {
        return map { String(format: "%02hhx", $0) }.joined()
    }

    var decimalString: String {
        return map { String(format: "%d", $0) }.joined()
    }

}

Your test string "UK"

let string = "UK"

Evaluates with

let hexString = string.data(using: .ascii)!.hexString

To

554b

And with

let decimalString = string.data(using: .ascii)!.decimalString

To

8575

Both results are correct, you can look them up in any ASCII table.