Scala学习（二）

二、Scala基础

1、变量：三种修饰符 -> ①val 常亮②var 变量③lazy val 惰性变量求值

2、类型

3、代码块 Block

{exp1;exp2}

或

{

exp1

exp2

}

4、函数

def functionName(param : paramType) : ReturnType = {

//function body : expressions

}

5、if表达式

if() val A else val B

6、for comprehension

用于循环的推导式

for {

x -> xs

y = x + 1

if (y > 0)

} yield y

7、match表达式

exp match {

case p1 => val 1

case p2 => val 2

……

case_ => val n

}

练习：

1、取得下面字符串中的汉字。
1477489369 0:0:0:0:0:0:0:1 cd60e43df3df2b490c517fff502f0684 3 1da6058be377160b14230637662921d7 (0,0,0,5,0,0,0,0) (SEARCH://search-fenzhi&desc-毛衣-male/?productList%5B1%5D%3D100129971676) NOCHANNEL QD_yyb R_84f63572b236e9e49f2e2e5cf885eb94 tag_sea

 object ScalaTest1 {

   def getChineseChar(str: String): Unit = {
     val regex = "[\u4e00-\u9fa5]".r
     var l = regex findAllIn str toList

     for {
       s <- l
     } yield (print(s))
   }

   def main(args: Array[String]): Unit = {
     val str1: String = "1477489369"
     val str2: String = "0:0:0:0:0:0:0:1"
     val str3: String = "cd60e43df3df2b490c517fff502f0684"
     val str4: String = "3"
     val str5: String = "1da6058be377160b14230637662921d7"
     val str6: String = "(0,0,0,5,0,0,0,0)"
     val str7: String = "(SEARCH://search-fenzhi&desc-毛衣-male/?productList%5B1%5D%3D100129971676)"
     val str8: String = "NOCHANNEL"
     val str9: String = "QD_yyb"
     val str10: String = "R_84f63572b236e9e49f2e2e5cf885eb94"
     val str11: String = "tag_sea"

     val list = str1 :: str2 :: str3 :: str4 :: str5 :: str6 :: str7 :: str8 :: str9 :: str10 :: str11 :: Nil

     for {
       s <- list
     } getChineseChar(s)
   }
 }

 

　　

2、将下面的单词和数字按列对齐并打印到控制台。
毛衣 1
毛衣毛衣 2
毛衣毛衣毛衣 3
毛衣毛衣毛衣毛衣 4
毛衣毛衣毛衣毛衣毛衣 5
毛衣毛衣毛衣毛衣毛衣毛衣 6
毛衣毛衣毛衣毛衣毛衣毛衣毛衣 7
毛衣毛衣毛衣毛衣毛衣毛衣毛衣毛衣 8
毛衣毛衣毛衣毛衣毛衣毛衣毛衣毛衣毛衣 9
毛衣毛衣毛衣毛衣毛衣毛衣毛衣毛衣毛衣毛衣 10

 object ScalaTest2 {
   def forScala(n: Int): Unit =
     for (i <- 1 to n) {
       var str = new StringBuilder()
       for (j <- 1 to i) {
         str.append("毛衣")
       }
       str.append('\t')
       str.append(i)
       str.append('\n')

       print(str)
     }

   def main(args: Array[String]): Unit = {
     forScala(10)
   }
 }