getting list from scala object

Question

I'm new to scala and I'm trying to get to construct a list from another one which I get from a scala object this is my model:

case class Session(
    _id: Option[String],
    participants: Option[Seq[Participant]])
  case class Participant(
    contact: Contact,
    participantStatus: Option[String])

Contact.scala

  case class Contact(
    firstName: Option[FirstName],
    lastName: Option[LastName],
    address: Option[Address])

Address.scala

  case class Address(
    email: Option[String])

using this loop:

for (s <- session.participants) println(s)

I get :

List(Participant(Contact(Some(FirstName(5m,Some(5),Some(5))),Some(LastName(5,Some(5),Some(5))),Some(Address(None,None,None,None,None,Some(5),Some(5),Some(5),Some([email protected]),None)),None,None),None), Participant(Contact(Some(FirstName(contact1,Some(contact1),Some(contact1))),Some(LastName(contact1,Some(contact1),Some(contact1))),Some(Address(None,None,None,None,None,Some(1),Some(1),Some(1),Some([email protected]),None)),None,None),None))

when I try : println(s.contact) I get : value contact is not a member of Seq[models.Session.Participant]

could you give us the initialisation of your value session ? I have some code : for(s <- session.participants) s.map(s => println(s.contact)) but I cannot test it :p — Daniel
– Daniel, Commented Jun 21, 2016 at 11:32
it's working: Some(Address(None,None,None,None,None,Some(1),Some(1),Some(1),Some(email1@gmail.‌com),None)) but now how can I access the email? — Rajeun
– Rajeun, Commented Jun 21, 2016 at 11:46
s.contact.address.email should do the trick ? But you should be careful with all those option and do some matching to see if it's there or not (this helped me when I was learning Options : danielwestheide.com/blog/2012/12/19/…) — Daniel
– Daniel, Commented Jun 21, 2016 at 11:50
thank you so much, but when using println(s.contact.address.email)) I get the same error: value email is not a member of Seq[models.Address] — Rajeun
– Rajeun, Commented Jun 21, 2016 at 11:54
s.map(s => s.contact.address.map( a => println(a.email))), would that work ? — Daniel
– Daniel, Commented Jun 21, 2016 at 12:34

insan-e · Accepted Answer · 2016-06-21 11:31:44Z

3

Your s variable is getting pulled out from session.participants which has type Option[Seq[Participant]], so you get Seq[Participant]. If you want to loop through your participants, you need a list/seq, so:

val sessionParticipants = session.participants.getOrElse(Seq.empty)
for (s <- sessionParticipants) println(s)

answered Jun 21, 2016 at 11:31

insan-e

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3 Comments

Jens Schauder Over a year ago

You might want to change participants: Option[Seq[Participant]] into participants: Seq[Participant] a Option of a Seq is a little strange, since a Seq already has an Nullobject: the empty Seq

Rajeun Over a year ago

yes I see thank you very much for your help, another last thing: when using for (s <- sessionParticipants) println(s.contact.address) I get Some(Address(None,None,None,None,None,Some(1),Some(1),Some(1),Some([email protected]),None)) how can I get the email?

insan-e Over a year ago

val maybeEmail = s.contact.address.flatMap(_.email) should be Option[String]. Then you can specify a fallback email with getOrElse, or, if you are 100% that every time you will have an email, you can call get on it... ;)

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