Converting a byte array into a hex string

As I am on Kotlin 1.3 you may also be interested in the UByte soon (note that it's an experimental feature. See also Kotlin 1.3M1 and 1.3M2 announcement)

E.g.:

@ExperimentalUnsignedTypes // just to make it clear that the experimental unsigned types are usedfun ByteArray.toHexString() = asUByteArray().joinToString("") { it.toString(16).padStart(2, '0') }

The formatting option is probably the nicest other variant (but maybe not that easily readable... and I always forget how it works, so it is definitely not so easy to remember (for me :-)):

fun ByteArray.toHexString() = joinToString("") { "%02x".format(it) }

printf does what we want here:

fun ByteArray.toHexString() : String {    return this.joinToString("") {        java.lang.String.format("%02x", it)    }}

This question has been answered, but I did not like the formatting. Here is something that formats it into something more readable ... at least for me.

@JvmOverloadsfun ByteArray.toHexString(separator: CharSequence = " ",  prefix: CharSequence = "[",  postfix: CharSequence = "]") =    this.joinToString(separator, prefix, postfix) {        String.format("0x%02X", it)    }

output:

[0x10 0x22]