Kotlin hashMapOf()

In Kotlin, the hashMapOf() function is used to create a new mutable HashMap. This function returns a reference to the newly created HashMap. You can specify the initial values of the HashMap while creating it using the hashMapOf() function.

Syntax

The syntax of the hashMapOf() function is as follows:

fun <K, V> hashMapOf(vararg pairs: Pair<K, V>): HashMap<K, V>

where:

• K is the key type.
• V is the value type.
• pairs are the pairs of key-value entries to be added to the HashMap.

Example

Here's an example of using the hashMapOf() function to create a new HashMap:

val fruits = hashMapOf(
    Pair("apple", 10),
    Pair("banana", 20),
    Pair("orange", 30)
)

In the above example, we created a new HashMap called fruits. The keys are String values representing the names of fruits, and the values are Int values representing the quantity of each fruit.

Output

When you run the above example, no output will be produced. The hashMapOf() function simply returns a reference to the newly created HashMap.

Explanation

The hashMapOf() function is a convenient way to create a new mutable HashMap in Kotlin. You can specify the initial values of the HashMap while creating it using the hashMapOf() function by passing a list of Pair objects representing the key-value entries.

In the example above, we created a new HashMap called fruits and initialized it with three key-value entries using Pair objects. You can access the values in the HashMap using their corresponding keys.

Use

The hashMapOf() function is useful when you need to create a new mutable HashMap in Kotlin and optionally initialize it with some key-value entries.

You can use mutable HashMaps to store and manipulate key-value pairs. HashMaps are often used in scenarios such as:

• Storing configuration data
• Caching frequently used data
• Maintaining session data

Important Points

• The hashMapOf() function returns a reference to the new HashMap that has been created.
• You can specify the initial values of the HashMap while creating it using the hashMapOf() function.
• The keys in the HashMap must be unique. If you add a key that already exists, the existing value will be overridden with the new value.

Summary

In this tutorial, we discussed the hashMapOf() function in Kotlin, which is used to create a new mutable HashMap and optionally initialize it with some key-value entries. We covered the syntax, example, output, explanation, use, and important points about the hashMapOf() function. With this knowledge, you can now create and initialize new HashMaps in Kotlin.