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scala basics

2022-08-10 15:21:00 【S_ng】

 1、基本语法

       o 区分大小写
        o 类名：首字母要大写,如 class HelloWorld{},class 
        Person{},class Student{},也称大驼峰
        o 方法名称：首字母小写,从第 2 个单词开启的首字段大写,如
        def toString(),def getName(),即为小驼峰
        o 程序文件名：保持与类名或对象名一致,区分大小写,以
        ".scala"来结尾.
        o 主程序入口：def main(args: Array[String]) ,scala To run independently
        必须从 main 方法开始处理,每个 scala 强制程序入口.

2、关键字
        o The following are reserved keywords,Do not use keywords as variable names.
        abstract case catch class
        def do else extends
        false final finally for
        forSome if implicit import
        lazy match new null
        object override package private
        protected return sealed super
        this throw trait trytrue type val var while with yield - : = => <- <: <% >: # @

3、数据类型

        与 Java 相似部分（皆为对象类型,scala 无原生数据类型）Byte,Short,Int,Long,Float,Double,Char,String,Boolean

4、运算符

        无自增自减,其余和java相同.

5、循环

while
        
def main(args: Array[String]): Unit = {
        var end = 10;
        var begin = 0;
        while (begin < end) {
        println(begin);
        begin = begin + 1;
        }
}

do...while
def main(args: Array[String]): Unit = {
        var end = 10;
        var begin = 0;
do {
        println(begin);
        begin = begin + 1;
    } while (begin < end)
  }
for 循环
        
def main(args: Array[String]): Unit = {
        var end = 10;
        var begin = 0;
        for(x <- begin to end){
                println(x)
                }
        }
double variable loop
        
def main(args: Array[String]): Unit = {
        var end = 5;
        var begin = 1;
        for(x <- begin to end;j <- begin to end){
        println(x+"*"+j)
               }
        }
集合循环
        
def main(args: Array[String]): Unit = {
        val stringList = List("one","two","three","four","five","six");
                for(str <- stringList){
        println(str)
                }
        }
Filtered in the loop
def main(args: Array[String]): Unit = {
        val stringList = List("one","two","three","four","five","six");
        for(str <- stringList if(str!="two" && str!="three")){
                println(str)
                }
        }
6、字符串
                在 Scala 中,字符串的类型实际上是 Java String,它本身没有
                String 类.
                完全与 java.lang.String 对等

原网站

版权声明
本文为[S_ng]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/222/202208101443547844.html

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