maxWith

Returns the first character having the largest value according to the provided comparator.

@JvmName(name = "maxWithOrThrow")fun CharSequence.maxWith(comparator: Comparator<in Char>): Char(source)

val text = "kotlin"
val maxChar = text.maxWith(Comparator<Char> { a, b -> a.compareTo(b) })
println("Maximum character: $maxChar")   // prints: t

Source