filterNot
Returns a char sequence containing only those characters from the original char sequence that do not match the given predicate.
inline fun CharSequence.filterNot(predicate: (Char) -> Boolean): CharSequence(source)
val original = "Kotlin is fun!"
val withoutVowels = original.filterNot { it.lowercaseChar() in "aeiou" }
println(withoutVowels) // Prints: Ktl n s fn!