Pair in Kotlin

What is Pair in Kotlin?

Pair in Kotlin is a standard library class that represents a simple tuple of two values. Pair in Kotlin is a generic class, allowing you to define the types of its two components independently. The primary purpose of Pair in Kotlin is to group two values together, providing a convenient way to work with related data as a single entity.

Creating and Using Pairs in Kotlin

Class Definition

where:

• A –
  type of the first value

• B –
  type of the second value

Constructor

In Kotlin, a constructor is a special member function that gets called when an object of a class is being created, mainly for the purpose of initializing variables or properties. To instantiate a new object of the Pair in Kotlin, the following constructor is used.

Code:

Here's an example demonstrating the creation of a Pair in Kotlin using the constructor.

Code:

Output:

Explanation:

In this example, a Pair in Kotlin is instantiated with values 1 and "Shubham", and the main() function uses destructuring declarations to assign these values to variables x and y, respectively.

Properties

The values within a pair can be obtained either by assigning them to a single variable or by utilizing the first and second properties for extraction.

• first:
  This property holds the first value of the pair.
• second:
  This property stores the second value of the pair.

Here's a program illustrating how to access the values of a pair in Kotlin using these properties.

Code:

Output:

Explanation:

In this example, a Pair in Kotlin is declared with the values 1 and "Shubham".

Functions

One of the functions available for the Pair in Kotlin is toString(), which provides the string representation of the pair.

• toString():
  This function returns a string equivalent of the pair.

Here's a program showcasing the usage of the toString() function with a pair in Kotlin:

Code:

Output:

Explanation:

In this example, two pairs are created – one with character values and another with a string and a list. The toString() function is then applied to each pair, and the resulting string representations are printed. This function is useful for obtaining a readable representation of the Pair instance.

Extension Functions

Extension functions empower us to add the functionalities of existing classes without the need for inheritance.

• toList():
  This extension function returns the List equivalent of a given Pair in Kotlin.

The declaration of the extension function is as follows.

Code:

Now, let us see a Kotlin program that uses this extended function on a pair in Kotlin.

Code:

Output:

Explanation:

In this example, three pairs are created – with character values, integer values and with strings. The toList() extension function is then applied to each pair, converting them into lists. The resulting lists (list1, list2, list3) are printed. This extension function enhances the versatility of the Pair in Kotlin by allowing it to be transformed into a List.

Advantages of Using Pairs in Kotlin

• Pair in Kotlin provides a concise and readable way to represent and work with pairs of values. The syntax is straightforward, contributing to more readable code.
• Kotlin's support for destructuring declarations allows developers to easily extract values from a Pair in Kotlin into separate variables, enhancing code readability and reducing verbosity.
• Developers can extend the functionality of the Pair in Kotlin using extension functions like toList(), allowing for additional operations or conversions. This enhances the flexibility of working with pairs.
• Pair in Kotlin provides a human-readable toString() representation, making it easier to debug and log the content of pairs during development.
• Pair in Kotlin is versatile and can be used to represent pairs of values of different types, making it applicable in various scenarios where related data needs to be grouped together.

Triple: An Extension of Pair in Kotlin

In Kotlin, a Triple is an extension of the Pair class, allowing developers to work with three related values as a single unit. Similar to Pair, Triple provides a convenient way to group and manage a triplet of data in a concise manner. Here's an overview of the Triple class:

Declaration

The Triple class is declared as a generic data class that can hold three values of potentially different types.

Code:

Initialization

Code:

Accessing Elements:

Individual elements of a Triple can be accessed using the .first, .second, and .third properties.

Code: