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…

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…

1. Variables (1) Three ways to define variables: 1) val refers to define an immutable variable; scala> val x = x: Int = scala> x*x res4: Int = scala> res4 + # use result as a value res6: Int = scala> res4 + res6 res7: Int = scala> x = # x i…

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. The three principles of OOP are encapsulation(封装性), inheritance(继承性) and polymorphism(多态性). example: class Shape{ def area: Double = 0.0 } # supertype # subtypes class Rectangle(val width: Double, val height: Double) extends Shape{ override def ar…

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")} |…

1. Functional programming treats computation as the evaluation of mathematical and avoids state and mutable data. Scala encourages an expression-oriented programming(EOP) 1) In expression-oriented programming every statement is an expression. A state…

1. Scala is a contraction of "scalable" and "language". It's a fusion of objected-oritended and functional programming. 2. Compare Book class between Java and Scala Java: class Book{ private String title; private int numberOfPages; pub…

scala语言的一大重要特性之一就是模式匹配.在我看来,这个怎么看都很像java语言中的switch语句,但是,这个仅仅只是像(因为有case关键字),他们毕竟是不同的东西,switch在java中,只能是用在函数体类的,且需要结合break使用.但是,在scala语言中,pattern matching除了有case关键字,其他,似乎和java又有很多甚至完全不同的东西. scala在消息处理中为模式匹配提供了强大的支持! 下面看看模式匹配的英文定义: A pattern match incl…