Scala 面试题与答案
问题 11. Explain the 'self' type in Scala.
The 'self' type is a way to declare the type of 'this' within a class or trait. It is often used in situations where the type of 'this' needs to be specified explicitly.
问题 12. What is the 'type' keyword used for in Scala?
The 'type' keyword is used to define type aliases in Scala. It allows developers to create alternative names for existing types, improving code readability and maintainability.
问题 13. Explain the concept of covariance and contravariance in Scala.
Covariance allows a type parameter to vary in the same direction as the container type, while contravariance allows it to vary in the opposite direction. They are denoted by + and - symbols, respectively.
问题 14. What is the purpose of the 'Seq' trait in Scala?
'Seq' is a trait in Scala that represents sequences—ordered collections of elements. It is a subtrait of 'Iterable' and provides methods for indexing, length, and more.
问题 15. Explain the 'copy' method in case classes.
The 'copy' method is automatically generated for case classes in Scala. It allows you to create a new instance of the case class with some fields modified, providing a convenient way to copy and update objects.
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