Collection Operations

Kotlin cung cấp nhiều **operations** mạnh mẽ cho collections: **Aggregations:** - sum(), average(), count() - max(), min(), maxBy(), minBy() **Transformations:** - sorted(), sortedBy(), sortedDescending() - reversed(), shuffled() - distinct(), take(n), drop(n) **Access:** - first(), last(), firstOrNull() - find { }, findLast { }