scala基础语法-match模式匹配

package org.xj.scala.spark

/**

* 模式匹配

*/

class Basic5 {

}

//样例类，不可变性，val定义，不建议var ||-->常用于模式匹配

/**

* case class(多用在匹模式匹配中)

* 构造器中的每一个类型都为val，不建议使用var

* 不用new就可以直接产生对象(为什么?apply方法)

*/

case class Book(name: String, author: String)

object Basic5 extends App {

val value = 3

val result = value match { //判断value值，返回值由下面判断结果确定

case 1 => "one"

case 2 => "two"

case _ => "some other number" //如果什么都不是

}

val result2 = value match {

case i if i == 1 => "one"

case i if i == 2 => "two"

case _ => "some othor number"

}

// println("resule1 of match is:" + result)

// println("resule2 of match is:" + result2);

//类型匹配

def t(obj: Any) = obj match { //Any任何类型

case x: Int => println("Int") //x代表传入的值

case s: String => println("String") //s代表传入的值

case _ => println("unknown type") //任何类型

}

//t("1")

val macTalk = Book("xiaohua", "CJQ")

macTalk match { //模式匹配macTalk的值

case Book(name, author) => println("this is book")

case _ => println("unknown")

}

}