ISO
ISO 8601 extended format.
Examples: 12:34, 12:34:56, 12:34:56.789, 12:34:56.1234.
When formatting, seconds are always included, even if they are zero. Fractional parts of the second are included if non-zero.
Guaranteed to parse all strings that LocalTime.toString produces.
See ISO-8601-1:2019. Any of the extended formats in 5.3.1.2b), 5.3.1.4a), and 5.3.1.3a) can be used, depending on whether seconds and fractional seconds are non-zero. The length of the fractional part is flexible between one and nine digits. The only allowed separator between seconds and fractional seconds is the dot .. We forbid using the time designator T to allow for a predictable composition of formats: see the note at the end of rule 5.3.5.
Samples
import kotlinx.datetime.*
import kotlinx.datetime.format.*
import kotlin.random.*
import kotlin.test.*
fun main() {
//sampleStart
// Parsing and formatting LocalTime values using the ISO format
val timeWithNanoseconds = LocalTime(hour = 8, minute = 30, second = 15, nanosecond = 160_000_000)
val timeWithSeconds = LocalTime(hour = 8, minute = 30, second = 15)
val timeWithoutSeconds = LocalTime(hour = 8, minute = 30)
check(LocalTime.Formats.ISO.parse("08:30:15.16") == timeWithNanoseconds)
check(LocalTime.Formats.ISO.parse("08:30:15") == timeWithSeconds)
check(LocalTime.Formats.ISO.parse("08:30") == timeWithoutSeconds)
check(LocalTime.Formats.ISO.format(timeWithNanoseconds) == "08:30:15.16")
check(LocalTime.Formats.ISO.format(timeWithSeconds) == "08:30:15")
check(LocalTime.Formats.ISO.format(timeWithoutSeconds) == "08:30:00")
//sampleEnd
}