kotlin-stdlib/kotlin.text/HexFormat/BytesHexFormat/groupSeparator

groupSeparator

val groupSeparator: String(source)

The string used to separate adjacent groups in a line, two space characters (" ") by default.

The number of bytes in each line and each group is determined by the bytesPerLine and bytesPerGroup options, respectively.

When formatting, adjacent groups within each line are separated by this string.

When parsing, adjacent groups within each line must be separated by this string. The parsing of this separator is performed in a case-insensitive manner.

Since Kotlin

1.9

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   val data = ByteArray(7) { it.toByte() }

// By default, both bytesPerLine and bytesPerGroup are set to Int.MAX_VALUE, which exceeds data.size.
// Hence, all bytes are formatted as a single line and a single group.
println(data.toHexString()) // 00010203040506
println("\"00010203040506\".hexToByteArray().contentEquals(data) is ${"00010203040506".hexToByteArray().contentEquals(data)}") // true

// Setting bytesPerGroup to 2 with the default group separator, which is two spaces.
val twoPerGroupFormat = HexFormat {
    bytes.bytesPerGroup = 2
}
println(data.toHexString(twoPerGroupFormat)) // 0001  0203  0405  06
println("\"0001  0203  0405  06\".hexToByteArray(twoPerGroupFormat).contentEquals(data) is ${"0001  0203  0405  06".hexToByteArray(twoPerGroupFormat).contentEquals(data)}") // true

// Specifying a custom group separator, a dot in this case.
val dotGroupSeparatorFormat = HexFormat {
    bytes {
        bytesPerGroup = 2
        groupSeparator = "."
    }
}
println(data.toHexString(dotGroupSeparatorFormat)) // 0001.0203.0405.06
println("\"0001.0203.0405.06\".hexToByteArray(dotGroupSeparatorFormat).contentEquals(data) is ${"0001.0203.0405.06".hexToByteArray(dotGroupSeparatorFormat).contentEquals(data)}") // true

// If bytesPerLine is less than or equal to bytesPerGroup, each line is treated as a single group,
// hence no group separator is used.
val lessBytesPerLineFormat = HexFormat {
    bytes {
        bytesPerLine = 3
        bytesPerGroup = 4
        groupSeparator = "|"
    }
}
println(data.toHexString(lessBytesPerLineFormat)) // 000102\n030405\n06
println("\"000102\\n030405\\n06\".hexToByteArray(lessBytesPerLineFormat).contentEquals(data) is ${"000102\n030405\n06".hexToByteArray(lessBytesPerLineFormat).contentEquals(data)}") // true

// When bytesPerLine is greater than bytesPerGroup, each line is split into multiple groups.
val moreBytesPerLineFormat = HexFormat {
    bytes {
        bytesPerLine = 5
        bytesPerGroup = 2
        groupSeparator = "."
    }
}
println(data.toHexString(moreBytesPerLineFormat)) // 0001.0203.04\n0506
println("\"0001.0203.04\\n0506\".hexToByteArray(moreBytesPerLineFormat).contentEquals(data) is ${"0001.0203.04\n0506".hexToByteArray(moreBytesPerLineFormat).contentEquals(data)}") // true

// Parsing fails due to incorrect group separator.
// "0001  0203  04\n0506".hexToByteArray(moreBytesPerLineFormat) // will fail with IllegalArgumentException 
   //sampleEnd
}