CODEWITHSUNDEEP
scalafor-loopfor-comprehension
François Bourrée
François Bourrée

Reputation: 17

Scala - error "value map is not a member of"

Using Scala, I have got this error "value map is not a member of chemins.Point" point <- segment.to

Here is my code : 

package chemins

case class Point(name: String, x: Long, y: Long)

case class Segment(from: Point, to: Point) {
  def distance: Double = {

    math.sqrt((from.x - to.x)*(from.x - to.x) + (from.y - to.y)*(from.y - to.y))
  }

}

case class Path(segments: Vector[Segment]) {

  def length: Double = {

    (for {

      segment <- segments

    } yield segment.distance).sum

  }

  def stops : Vector[Point] = {

    for {
      segment <- segments
      point <-  segment.to
    } yield point
  }


}

From my previous search, it seems to come from the fact that "to" has no generator but I have no clues if it's relevant.

Thanks !

Upvotes: 1

Views: 2520

Answers (1)

Andrey Tyukin
Andrey Tyukin

Reputation: 44908

Without looking at the chemins api, you most likely want

for { segment <- segments } yield segment.to

or

for { 
  segment <- segments
  point = segment.to
} yield point

Trying to use segment.to as a generator makes no sense, because it's not a collection or a .map-pable entity.

Also note that this for-comprehension reduces to

segments.map(_.to)

Upvotes: 3

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