HexFormat

import kotlin.test.*

fun main() { 
   //sampleStart 
   // Specifying format options for numeric values.
println(58.toHexString(HexFormat { number.removeLeadingZeros = true })) // 3a
println("0x3a".hexToInt(HexFormat { number.prefix = "0x" })) // 58

// Specifying format options for byte arrays.
val macAddressFormat = HexFormat {
    upperCase = true
    bytes {
        bytesPerGroup = 2
        groupSeparator = "."
    }
}
val macAddressBytes = byteArrayOf(0x00, 0x1b, 0x63, 0x84.toByte(), 0x45, 0xe6.toByte())
println(macAddressBytes.toHexString(macAddressFormat)) // 001B.6384.45E6
println("\"001B.6384.45E6\".hexToByteArray(macAddressFormat).contentEquals(macAddressBytes) is ${"001B.6384.45E6".hexToByteArray(macAddressFormat).contentEquals(macAddressBytes)}") // true

// Creating a format that defines options for both byte arrays and numeric values.
val customHexFormat = HexFormat {
    upperCase = true
    number {
        removeLeadingZeros = true
        prefix = "0x"
    }
    bytes {
        bytesPerGroup = 2
        groupSeparator = "."
    }
}
// Formatting numeric values utilizes the `upperCase` and `number` options.
println(58.toHexString(customHexFormat)) // 0x3A
// Formatting byte arrays utilizes the `upperCase` and `bytes` options.
println(macAddressBytes.toHexString(customHexFormat)) // 001B.6384.45E6 
   //sampleEnd
}