Kotlin create new object using another object as the default constructor params

Question

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

Is there a simple way to create a new Person object using another object as a template to fill in the required constructor params?

// Example of what I'd like to be able to do

val person1 = Person(age = 35, name = "Cory")

val person2 = Person(person1, name = "Jeff")

Héctor Valls · Accepted Answer · 2021-01-29 13:25:02Z

2

You can use copy() method, available in data classes, and override parameters you want to change:

val person1 = Person(age = 35, name = "Cory")
val person2 = person1.copy(name = "Jeff")

answered Jan 29, 2021 at 13:25

Héctor Valls

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Comments

ChristianB · Accepted Answer · 2021-01-29 13:24:43Z

2

Every data class in Kotlin has a copy function:

val person2 = person1.copy(name = "Jeff") // but its age is still 35 (from Cory)

All parameters are optional in the copy function, so you can overwrite / change the ones you like.

Note that the copy() call performs a shallow copy

answered Jan 29, 2021 at 13:24

ChristianB

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