CODEWITHSUNDEEP
androidkotlin
Walt
Walt

Reputation: 111

Request data from object 2 that has the id of object 1 as attribute

I have 2 data classes, Person and Dog. Person has the following attributes:

personId, name, age, isFemale

data class Person (
  val personId: Int,
  val name: String,
  val age: Int,
  val isFemale: Boolean
)

Dog has the following attributes:

dogId, personId, name, age, isFemale

data class Dog (
  val dogId: Int,
  val personId: Int,
  val name: String,
  val age: Int,
  val isFemale: Boolean
)

I want to request all the dogs of a person, by using the id attribute. But I receive an error that dogs is not initialized and empty.

fun getTestPersons(): Array<Person>{
  return arrayOf(): Array<Person>(
   Person(1, "Harry", 35, false)
)
}

fun getTestDogs(): Array<Dog>{
  return arrayOf(
   Dog(1, 1, "Bert", 4, false), Dog(2, 1, "Linda", 6, true)
)
}

currentPerson has been initialized with for example the first one.

lateinit var dogs: MutableList<Dog>
for(dog in getTestDogs()){
if(dog.personId == currentPerson.personId){
  dogs.add(dog)
 }
}

Expected: A MutableList with all the dogs of a specific person.

Upvotes: 0

Views: 23

Answers (1)

triad
triad

Reputation: 21537

The Collection.filter function is perfect for this

getTestDogs()
  .filter { dog -> dog.personId == currentPerson.personId }
  .toMutableList()

Upvotes: 1

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