Swift3 convert string value to hexadecimal string - ios

Question

I am new to Swift and I want to convert a string into hexadecimal string. I have found a Objective-C function to a string into hexadecimal.
NSString * str = #"Say Hello to My Little Friend";
NSString * hexString = [NSString stringWithFormat:#"%#",
[NSData dataWithBytes:[str cStringUsingEncoding:NSUTF8StringEncoding]
length:strlen([str cStringUsingEncoding:NSUTF8StringEncoding])]];
for (NSString * toRemove in [NSArray arrayWithObjects:#"<", #">", #" ", nil])
hexString = [hexString stringByReplacingOccurrencesOfString:toRemove withString:#""];
NSLog(#"hexStr:%#", hexString);
Now I am unable to convert this function in Swift. Currently I am using Swift3.
Please someone can do this for me?

Answer 1

This produces the same output as the ObjC version
let str = "Say Hello to My Little Friend"
let data = Data(str.utf8)
let hexString = data.map{ String(format:"%02x", $0) }.joined()

Answer 2

Details
Xcode 11.2.1 (11B500), Swift 5.1
Solution
extension String {
func toHexEncodedString(uppercase: Bool = true, prefix: String = "", separator: String = "") -> String {
return unicodeScalars.map { prefix + .init($0.value, radix: 16, uppercase: uppercase) } .joined(separator: separator)
}
}
Usage
let str = "Hello, playground"
print(str.toHexEncodedString()) // 48656C6C6F2C20706C617967726F756E64
print(str.toHexEncodedString(uppercase: false, prefix: "0x", separator: " ")) // 0x48 0x65 0x6c 0x6c 0x6f 0x2c 0x20 0x70 0x6c 0x61 0x79 0x67 0x72 0x6f 0x75 0x6e 0x64

Answer 3

Convert your string to NSData like this.
let myString = "ABCDEF"
let data = myString.dataUsingEncoding(NSUTF8StringEncoding)
Then convert the NSData to hexadecimal string using following method -
func hexFromData(data:NSData) -> String {
let p = UnsafePointer<UInt8>(data.bytes)
let len = data.length
var str: String = String()
for i in 0...len-1 {
str += String(format: "%02.2X", p[i])
}
return str
}
Hope this helped.

Answer 4

Please try this,
let string = "Say Hello to My Little Friend"
let data = string.dataUsingEncoding(NSUTF8StringEncoding)
print(data)
and its output is:
Optional(<53617920 48656c6c 6f20746f 204d7920 4c697474 6c652046 7269656e 64>)

Answer 5

Swift 3
let string = "Hello World!"
let data = string.data(using: String.Encoding.utf8)
let hexString = data?.hex
extension Data {
var hex: String {
var string = ""
#if swift(>=3.1)
enumerateBytes { pointer, index, _ in
for i in index..<pointer.count {
string += String(format: "%02x", pointer[i])
}
}
#else
enumerateBytes { pointer, count, _ in
for i in 0..<count {
string += String(format: "%02x", pointer[i])
}
}
#endif
return string
}
}