/**
* Removes all alphabetic characters (letters) from a given string,
* leaving numbers, symbols, and whitespace intact.
*
* This approach uses [Char.isLetter], which provides full Unicode support
* (handling accented characters, Cyrillic, etc., out of the box).
*
* @param input The alphanumeric string to process.
* @return A new string with all letters removed.
*/
fun removeLetters(input: String): String {
// filterNot keeps only the characters that are NOT letters
return input.filterNot { it.isLetter() }
}
fun main() {
val mixedString = "abc123XYZ456programming789"
val result = removeLetters(mixedString)
println(result)
}
/*
run:
123456789
*/
