kotlin-stdlib / kotlin.sequences / count count Common JVM JS Native 1.0 fun <T> Sequence<T>.count(): Int(source) Returns the number of elements in this sequence. The operation is terminal. Common JVM JS Native 1.0 inline fun <T> Sequence<T>.count( predicate: (T) -> Boolean): Int(source) Returns the number of elements matching the given predicate. The operation is terminal.