scala 中常见类型 类型层次结构和类型转换

 基本数据类型

层次图

 类型层次图

类型转换:

 

scala> val a:Int =3;
a: Int = 3

scala> val b = a+2.21;
b: Double = 5.21

b 变量 自动变成 Double类型 

 

scala> val c = (a+2.21).toInt;
c: Int = 5

将Double 类型 强制转换成Int 类型  造成了精度损失.

 代码测试如下:

scala> val a=10;
a: Int = 10

scala> val b= a+"";
b: String = 10

scala> val c = a.toString;
c: String = 10

scala> println(a+10,b+10,c+10);
(20,1010,1010)

scala> val s1 ="123";
s1: String = 123

scala> val s2 ="12.3"
s2: String = 12.3

scala> val s3 = "false"
s3: String = false

scala> val a=s1.toInt;
a: Int = 123

scala> val b= s2.toDouble;
b: Double = 12.3

scala> val c = s3.toBoolean;
c: Boolean = false