scala for

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scala> for {
     |   s <- Array("a","b","c")
     | }
     | println(s)
a
b
c

scala> for {
     |   i <- 1 to 5
     |   j <- 1 to 2
     | }
     | println(i * j)
1
2
2
4
3
6
4
8
5
10

if入れる系

scala> for {
     |   i <- 0 to 10
     |   if i % 2 == 0
     | }
     | println(i)
0
2
4
6
8
10

yield　= 値を返すfor

scala> for {
     |   i <- 1 to 5
     | } yield i
res8: scala.collection.immutable.IndexedSeq[Int] = Vector(1, 2, 3, 4, 5)

scala> 

scala> 

scala> def test = for {
     |   i <- 0 to 10
     |   if i % 2 == 0
     | } yield i
test: scala.collection.immutable.IndexedSeq[Int]

scala> test
res9: scala.collection.immutable.IndexedSeq[Int] = Vector(0, 2, 4, 6, 8, 10)

yieldに式も書ける

scala> for {
     |   i <- 1 to 5
     | } yield i * 2
res12: scala.collection.immutable.IndexedSeq[Int] = Vector(2, 4, 6, 8, 10)