Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

fun CharSequence.single(): Char

Returns the single character, or throws an exception if the char sequence is empty or has more than one character.

Platform and version requirements: JVM (1.0), JS (1.0), Native (1.0)

inline fun CharSequence.single(
    predicate: (Char) -> Boolean
): Char

Returns the single character matching the given predicate, or throws exception if there is no or more than one matching character.