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As i have one User class having 2 parameters : first_name, last_name. So my kotlin class with be :
data class User(val first_name:String, val last_name:String) Now i want a constructor which will accept only first_name, or you can say just one parameter. How can i define it with Kotlin?
I know we can pass default value and in that way we can ignore second parameter, but how can we write multiple constructor?
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Kotlin supports overloading for callables and properties, that is, the ability for several callables (functions or function-like properties) or properties with the same name to coexist in the same scope, with the compiler picking the most suitable one when such entity is referenced.
In Kotlin, you can also call a constructor from another constructor of the same class (like in Java) using this() .
Constructors. A class in Kotlin can have a primary constructor and one or more secondary constructors. The primary constructor is a part of the class header, and it goes after the class name and optional type parameters. The primary constructor cannot contain any code.
A Kotlin class can have following two type of constructors: Primary Constructor. Second Constructors.
A class in Kotlin can have a primary constructor and one or more secondary constructors. The primary constructor is part of the class header: it goes after the class name (and optional type parameters).
Kotlin | Method Overloading: Here, we are implementing a Kotlin program to demonstrate the example of method overloading. Function overloading or method overloading is the ability to create multiple functions of the same name with different implementations. Top Interview Coding Problems/Challenges!
Kotlin allows you to provide custom implementations for the predefined set of operators on types. These operators have predefined symbolic representation (like + or *) and precedence. To implement an operator, provide a member function or an extension function with a specific name for the corresponding type.
Overloaded constructor is called based upon the parameters specified when new is executed. When do we need Constructor Overloading? Sometimes there is a need of initializing an object in different ways. This can be done using constructor overloading.
You can define extra constructors in the class body
data class User(val firstName: String, val lastName: String) { constructor(firstName: String) : this(firstName, "") } These 'secondary constructors' have to call through to the primary constructor or a different secondary constructor. See the Official documentation on constructors.
So, in effect this is the same as just a primary constructor with default argument, which would be the idiomatic way to go.
data class User(val firstName: String, val lastName: String = "") If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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