Kotlin data class optional variable

Question

data class Student(     val id: Int?,     val firstName: String?,     val lastName: String?,     val hobbyId: Int?,     val address1: String?,     val address2: String?,     val created: String?,     val updated: String?,     ... ) 

I have like above data class, and I want to create a Student instance with only first name and last name. So If I run this,

// creating a student  Student(     firstName = "Mark"     lastName = "S" ) 

I will get No value passed for parameter 'id' ... errors.

To avoid that, I modified the Student class like this,

data class Student(     val id: Int? = null,     val firstName: String? = null,     val lastName: String? = null,     val hobbyId: Int? = null,     val address1: String? = null,     val address2: String? = null,     val created: String? = null,     val updated: String? = null,     ... ) 

But it looks so ugly.

Is there any better way?

Answer 1

You can set default values in your primary constructor as shown below.

data class Student(val id: Int = Int.MIN_VALUE,                val firstName: String,                val lastName: String,                val hobbyId: Int = Int.MIN_VALUE,                val address1: String = "",                val address2: String = "",                val created: String = "",                val updated: String = "") 

Then you can use named arguments when creating a new student instance as shown below.

Student(firstName = "Mark", lastName = "S")