Arrays in Kotlin

 In Kotlin, arrays are used to store multiple values of the same type in a single variable. Kotlin provides several ways to create and work with arrays. Here's an overview of arrays in Kotlin:

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1. Creating Arrays

Kotlin provides the arrayOf() function to create arrays of a specific type.

Example:

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val numbers = arrayOf(1, 2, 3, 4, 5) // Array of integers
val names = arrayOf("Alice", "Bob", "Charlie") // Array of strings

For primitive types, Kotlin provides specialized array classes like IntArray, DoubleArray, BooleanArray, etc., which are more efficient.

Example:

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val intArray = intArrayOf(1, 2, 3, 4, 5) // IntArray
val doubleArray = doubleArrayOf(1.1, 2.2, 3.3) // DoubleArray

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2. Accessing Array Elements

You can access array elements using the index operator [].

Example:

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val numbers = arrayOf(10, 20, 30, 40, 50)
println(numbers[0]) // Output: 10
println(numbers[2]) // Output: 30

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3. Modifying Array Elements

You can modify array elements by assigning a new value to a specific index.

Example:

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val numbers = arrayOf(10, 20, 30, 40, 50)
numbers[2] = 100
println(numbers[2]) // Output: 100

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4. Array Size

You can get the size of an array using the size property.

Example:

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val numbers = arrayOf(10, 20, 30, 40, 50)
println(numbers.size) // Output: 5

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5. Iterating Over Arrays

You can iterate over an array using a for loop or higher-order functions like forEach.

Example:

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val numbers = arrayOf(10, 20, 30, 40, 50)

// Using a for loop
for (number in numbers) {
    println(number)
}

// Using forEach
numbers.forEach { println(it) }

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6. Creating Arrays with a Fixed Size

You can create an array of a specific size using the Array constructor. The constructor takes the size and a lambda function to initialize each element.

Example:

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val squares = Array(5) { i -> (i + 1) * (i + 1) }
println(squares.joinToString()) // Output: 1, 4, 9, 16, 25

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7. Multidimensional Arrays

Kotlin supports multidimensional arrays, which are essentially arrays of arrays.

Example:

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val matrix = arrayOf(
    arrayOf(1, 2, 3),
    arrayOf(4, 5, 6),
    arrayOf(7, 8, 9)
)

println(matrix[1][2]) // Output: 6

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8. Common Array Functions

Kotlin provides several utility functions for arrays, such as:

• joinToString(): Converts the array to a string.

• sliceArray(): Returns a subarray.

• contains(): Checks if an element exists in the array.

• sort(): Sorts the array.

Example:

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val numbers = arrayOf(5, 3, 8, 1, 2)
println(numbers.joinToString(", ")) // Output: 5, 3, 8, 1, 2
println(numbers.sorted().joinToString(", ")) // Output: 1, 2, 3, 5, 8

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9. Primitive Type Arrays

For better performance, Kotlin provides specialized classes for arrays of primitive types:

• IntArray

• DoubleArray

• BooleanArray

• CharArray

• etc.

Example:

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val intArray = IntArray(5) { it * 2 } // [0, 2, 4, 6, 8]

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10. Nullability in Arrays

Kotlin allows you to create arrays of nullable types.

Example:

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val nullableArray = arrayOfNulls<String>(3) // Array of size 3 with null values
nullableArray[0] = "Kotlin"
println(nullableArray[1]) // Output: null

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Summary

• Use arrayOf() to create arrays.

• Use specialized classes like IntArray for primitive types.

• Access and modify elements using the index operator [].

• Use loops or higher-order functions to iterate over arrays.

• Kotlin arrays are mutable, but their size is fixed after creation.