scala

问题 I'm using Databricks Connect to run code in my Azure Databricks cluster locally from IntelliJ IDEA (Scala). Everything works fine. I can connect, debug, inspect locally in the IDE. I created a Databricks Job to run my custom app JAR, but it fails with the following exception: 19/08/17 19:20:26 ERROR Uncaught throwable from user code: java.lang.NoClassDefFoundError: com/databricks/service/DBUtils$ at Main$.<init>(Main.scala:30) at Main$.<clinit>(Main.scala) Line 30 of my Main.scala class is

问题 I would like to define a List of elements implementing a common type class. E.g. trait Show[A] { def show(a: A): String } implicit val intCanShow: Show[Int] = new Show[Int] { def show(int: Int): String = s"int $int" } implicit val stringCanShow: Show[String] = new Show[String] { def show(str: String): String = str } The problem is, how to define a list = List(1, "abc") such that it is guaranteed that a Show instance for these values is in scope? I would then like to map this list over show

问题 I would like to define a List of elements implementing a common type class. E.g. trait Show[A] { def show(a: A): String } implicit val intCanShow: Show[Int] = new Show[Int] { def show(int: Int): String = s"int $int" } implicit val stringCanShow: Show[String] = new Show[String] { def show(str: String): String = str } The problem is, how to define a list = List(1, "abc") such that it is guaranteed that a Show instance for these values is in scope? I would then like to map this list over show

问题 I am using the Scala 2.8 default parameters on a constructor, and for Java compatibility reasons, I wanted a no-arg constructor that uses the default parameters. This doesn't work for very sensible reasons: class MyClass(field1: String = "foo", field2: String = "bar") { def this() = { this() // <-- Does not compile, but how do I not duplicate the defaults? } } I am wondering if there is anything that I am missing. Any thoughts that don't require duplicating the parameter defaults? Thanks! 回答1

问题 I am using the Scala 2.8 default parameters on a constructor, and for Java compatibility reasons, I wanted a no-arg constructor that uses the default parameters. This doesn't work for very sensible reasons: class MyClass(field1: String = "foo", field2: String = "bar") { def this() = { this() // <-- Does not compile, but how do I not duplicate the defaults? } } I am wondering if there is anything that I am missing. Any thoughts that don't require duplicating the parameter defaults? Thanks! 回答1

问题 I am using the Scala 2.8 default parameters on a constructor, and for Java compatibility reasons, I wanted a no-arg constructor that uses the default parameters. This doesn't work for very sensible reasons: class MyClass(field1: String = "foo", field2: String = "bar") { def this() = { this() // <-- Does not compile, but how do I not duplicate the defaults? } } I am wondering if there is anything that I am missing. Any thoughts that don't require duplicating the parameter defaults? Thanks! 回答1

问题 I am using the Scala 2.8 default parameters on a constructor, and for Java compatibility reasons, I wanted a no-arg constructor that uses the default parameters. This doesn't work for very sensible reasons: class MyClass(field1: String = "foo", field2: String = "bar") { def this() = { this() // <-- Does not compile, but how do I not duplicate the defaults? } } I am wondering if there is anything that I am missing. Any thoughts that don't require duplicating the parameter defaults? Thanks! 回答1

问题 Suppose MyClass is a class defined in Java, and has many static as well as non-static members. I tried to alias this class (and associated companion object) in a Scala object MyObject as shown below: object MyObject { import javastuff._ type MyAlias = MyClass val MyAlias = MyClass } Scalac complains: error: object MyClass is not a value val MyAlias = MyClass How do I work around this? Thanks. 回答1: Although this works in pure Scala for a class + companion object, it's not possible with Java's

问题 Suppose MyClass is a class defined in Java, and has many static as well as non-static members. I tried to alias this class (and associated companion object) in a Scala object MyObject as shown below: object MyObject { import javastuff._ type MyAlias = MyClass val MyAlias = MyClass } Scalac complains: error: object MyClass is not a value val MyAlias = MyClass How do I work around this? Thanks. 回答1: Although this works in pure Scala for a class + companion object, it's not possible with Java's

问题 Suppose MyClass is a class defined in Java, and has many static as well as non-static members. I tried to alias this class (and associated companion object) in a Scala object MyObject as shown below: object MyObject { import javastuff._ type MyAlias = MyClass val MyAlias = MyClass } Scalac complains: error: object MyClass is not a value val MyAlias = MyClass How do I work around this? Thanks. 回答1: Although this works in pure Scala for a class + companion object, it's not possible with Java's