forのサンプル

for.scala

case class Student(name: String, age: Int, grade: Int)

val list = List(
  Student("Steve", 15, 1),
  Student("Chad", 16, 2),
  Student("Shigeru", 40, 1),
  Student("Chloé", 18, 3)
)

val students = for {
  student <- list
  name <- student.name
} yield name

println(students)

val studentNames = for {
  student <- list
} yield student.name

println(studentNames)