Scala的7种值类型和条件表达式以及for循环

        Byte
    Char
    Short
    Int
    Long
    Float
    Double

条件表达式

scala> val x = 3
x: Int = 3

scala> val y = if ( x > 1 ) 1 else -1
y: Int = 1

scala> println(y)
1

scala> val z = if ( x > 1 ) 1 else "error"
z: Any = 1

scala> val z = if ( x < 1 ) 1 else "error"
z: Any = error

scala> val a = if ( x < 1 ) 1
a: AnyVal = ()

scala> val a = if ( x < 1 ) 1 else()
a: AnyVal = ()

scala> val b = if ( x > 1 ) 1 else if ( x < 1 ) -1 else 0
b: Int = 1

for循环

scala> 1 to 10
res1: scala.collection.immutable.Range.Inclusive = Range(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)

scala> 1.to(10)
res2: scala.collection.immutable.Range.Inclusive = Range(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)

scala> 1 until 10
res3: scala.collection.immutable.Range = Range(1, 2, 3, 4, 5, 6, 7, 8, 9)

scala> for ( i <- 1 to 10 ) {
     | println(i)
     | }
1
2
3
4
5
6
7
8
9
10
scala> val arr = Array("java","scala","python")
arr: Array[String] = Array(java, scala, python)

scala> for ( i <- arr ) println(i)
java
scala
python

scala> for ( i <- 1 to 3; j <- 1 to 3 if ( i != j  ) ) println( i * 10 + j)
12
13
21
23
31
32


scala> for ( i <- 1 to 3 ) {
     | for ( j <- 1 to 3 ) {
     | if ( i != j ) println( i * 10 + j )
     | }
     | }
12
13
21
23
31
32
scala> val res = for ( i <- 1 until 10 ) yield i
res: scala.collection.immutable.IndexedSeq[Int] = Vector(1, 2, 3, 4, 5, 6, 7, 8, 9)

scala> println(res)
Vector(1, 2, 3, 4, 5, 6, 7, 8, 9)

scala> 1.+(3)
warning: there were 1 deprecation warning(s); re-run with -deprecation for details
res10: Double = 4.0