Recently I transit to use scala to program. scala is a functional and objected oriented language, but it has seamless java Interoperability (they both run in JVM and freely mixed). Compared to the java that I am familiar to,  there are some common co…

软件版本 软件信息 软件名称 版本 下载地址 备注 Java 1.8 https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html 64位版本的 Scala 2.10.5 https://www.scala-lang.org/download/2.10.5.html   SBT sbt 1.1.6 https://www.scala-sbt.org/download.html   SVN…

Scala List FAQ: How do I merge a List in Scala? NOTE: I wrote the solutions shown below a long time ago, and they are not optimal. I'll update this article when I have more time. The best approach is to prepend one List to the beginning of another Li…

One of the more powerful features Scala has is the ability to generically abstract across things that take type parameters. This feature is known as Higher Kinded Types (HKT). This feature allows us to write a library that works with a much wider arr…

Spark Streaming 编程指南 Overview A Quick Example Basic Concepts Linking Initializing StreamingContext Discretized Streams (DStreams) Input DStreams and Receivers Transformations on DStreams Output Operations on DStreams DataFrame and SQL Operations MLli…

1. Translating Java Classes to Scala Classes Example 1: # a class declaration in Java public class Book{} # Scala equivalent of a class declaration class Book Example 2: # a Java class with a Construtor public class Book{ private final int isbn; priv…

1. Unified Type System Scala has a unified type system, enclosed by the type Any at the top of the hierarchy and the type Nothing at the bottom of the hierarchy. All Scala types inherit from Any. # Using Any, Book extends AnyRef, and x is an Int that…

A trait provides code reusability in Scala by encapsulating method and state and then offing possibility of mixing them into classes thus allowing code reuse. #define Trait Gliding scala> trait Gliding{ | def gliding(){ println("gliding")} |…

Scala's object-oriented collections support mutable and immutable type hierarchies. Also support functional higher-order operations such as map, filter, and reduce that let you use expression-oriented programming in collections. Higher-order operatio…

The basic functional cornerstones of Scala: immutable data types, passing of functions as parameters and pattern matching. 1. Basic Pattern Matching In Scala, your cases can include types, wildcards, sequences, regular expressions, and so forth. scal…