check empty for option string in scala

Question

I want to check for empty string in scala .If the string is empty return an option else return a None

Updated 1

 case class Student(name:String,subject:Symbol = Symbol("Default")))

  def getStudentName(name :Option[String]):Option[Student]={
     name.flatMap(_ => Option(Student(name.get)))
  }

Updated 2

Scenario 1:

 call 1- print(getStudentName(Option("abc")))//Some(Student(abc))
 Call 2- print(getStudentName(Option("")))//return Some(Student())

Scenario 2:

case class Emp(id:Int)

  def getEmp(id:Option[String]):Option[Emp]={
    id.flatMap(_ => Option(Emp(id.get.toInt)))
  }

  print(getEmp(Option("123")))
  print(getEmp(Option("")))//gives number format exception

I want to return None when I pass ""

Tanjin · Accepted Answer · 2017-09-18T14:36:34.490

5

There is too much wrapping with Option going on, you can easily do:

Scenario 1:

name
  .filterNot(_.isEmpty)
  .map(Student(_))

Scenaro 2:

id
  .filterNot(_.isEmpty)
  .filter(_.matches("^[0-9]*$")) // ensure it's a number so .toInt is safe
  .map(id => Emp(id.toInt))

edited Sep 18 '17 at 14:36

answered Sep 18 '17 at 14:03

Tanjin

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thks it works but I have updated my question can u please check – coder25 Sep 18 '17 at 14:16
case where we need to change string to int-Can you please have a look at updated question – coder25 Sep 18 '17 at 14:17
Please check for scenerio 1 the `subject` field is also added which gives compile error with map – coder25 Sep 18 '17 at 14:33
That's because the original case class has an additional argument now. See updated answer – Tanjin Sep 18 '17 at 14:37
can u explain the _ used in scenerio 1 – coder25 Sep 18 '17 at 14:40
It's syntactic sugar, see a similar answer I did here: https://stackoverflow.com/questions/43302223/map-function-in-scala/43302468#43302468 – Tanjin Sep 18 '17 at 14:41
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/154703/discussion-between-coder25-and-tanjin). – coder25 Sep 18 '17 at 15:06
I have few more queries I have created a new question https://stackoverflow.com/questions/46282620/efficient-way-to-match-case-object-in-scala – coder25 Sep 18 '17 at 15:07

check empty for option string in scala

1 Answers1