1.流程控制
1)do..while
1 def doWhile(){ 2 var line="" 3 do{ 4 line = readLine() 5 println("readlineConetent" + line ) 6 }while(line != " ") 7 }
2)for
方式一:
1 for (arg <-args) 2 println(arg)
方式二:
1 for (i <- 1 to 10 if i % 2 == 0) 2 println(i)
for参数里面同样支持if判断。比如输出1——10中的偶数
1 for (i <- 1 to 10 if i % 2 == 0) 2 println(i)
增强for循环
1 //增强for循环 2 def doForStrenth(){ 3 var files = (new java.io.File(".")).listFiles() 4 for(file <- files){ 5 println(file) 6 } 7 }
3)while
1 var i=0 2 while (i < args.length) { 3 println (args(i)) 4 i+=1 5 }
4)if .. else .. (可以将结果直接赋值给一个变量)
1 var file = if(args.isEmpty) args(0) else "spark" 2 println(file)
注意:
1)Scala不支持i++和++i,需要使用i+=1来实现加一;
2.异常处理
try .. catch 机制,
1 //异常部分 2 def doException(){ 3 val n = 99 4 val file = "scala.text" 5 // OpenFileInputStreamAction 6 try { 7 val half = if (n % 2 == 0) n/2 else throw new RuntimeException("N must be event") 8 } catch { 9 case e: Exception => println("This exception is :" +e.getMessage() ) 10 } finally { 11 // close(file) 12 } 13
时间: 2024-07-30 23:52:41