Answers for "mutable lists kotlin"

mutable lists kotlin

val intList = listOf<Int>(5, 12)
val stringList = listOf<String>("1","2","3","4")

// Mutablelists
val intList = mutableListOf<Int>(5, 12)
val stringList = mutableListOf<String>("1","2","3","4")

// Array
val intList = arrayOf<Int>(5, 12)
val stringList = arrayOf<String>("1","2","3","4")

// Sized array
var table = Array<String>(words.size) {""}
val literals = arrayOf<String>("January", "February", "March")

// Create 2D Array
val grid = Array(rows) { Array(cols) { Any() } }

//String[] in Java equivalent Array<String> in Kotlin 
//eg.
var array1 : Array<String?> = emptyArray()
var array2: Array<String?> = arrayOfNulls(4)
var array3: Array<String> = arrayOf("Mashroom", "Kitkat", "Oreo", "Lolipop")

val num = arrayOf(1, 2, 3, 4)   //implicit type declaration
val num = arrayOf<Int>(1, 2, 3) //explicit type declaration

// Or you can also create typed lists, arrays, mutable lists
val intList = listOf<Int>(5, 12)
val listSample: List<Int> = listOf(1,2,3)
val mutableListSample: MutableList<Int> = mutableListOf(1,2,3)
val stringList = listOf<String>("1","2","3","4")
val stringListSample: List<String> = listOf<String>("1","2","3","4")
var initList = List(4){"s"} // {"s", "s", "s", "s"}

// Arrays
val intArray = arrayOf(1,2,3)
val intArray2: Array<Int> = arrayOf(1,2,3)
val intArray3 = intArrayOf(1,2,3)
val charArray = charArrayOf('a', 'b', 'c')
val intArray = arrayOf(1,2,3)
val intArray2: Array<Int> = arrayOf(1,2,3)
val intArray3 = intArrayOf(1,2,3)
val charArray = charArrayOf('a', 'b', 'c')
val stringArray = arrayOf("genesis", "melo")
val stringArray2: Array<String> = arrayOf("genesis", "melo")
val stringOrNulls = arrayOfNulls<String>(5) // returns Array<String?>
val stringOrNulls2: Array<String?> = arrayOf("", null)// returns Array<String?>
var emptyStringArray: Array<String> = emptyArray()
var emptyStringArray2: Array<String> = arrayOf()
var sizedEmptyArray = Array(4){"s"} // {"s", "s", "s", "s"}

// In this line, we create an array from a range of numbers.
val nums3 = IntArray(5, { i -> i * 2 + 3})
// This line creates an array with IntArray. It takes the number of elements and a factory function as parameters.
// This is the output. 
/*
[1, 2, 3, 4, 5]
[3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
[3, 5, 7, 9, 11]
*/

// You can read this as initialize an array of 5 elements, assign each item to its index times two
val array = Array(5) {it * 2}
// OR -> val array = List(5) {it * 2}
println(array.joinToString()) // 0, 2, 4, 6, 8

val list = List(5){ it.times(2) } // Creates List: [0, 2, 4, 6, 8]

val array = Array<Int>(5) { e -> if (e % 2 == 0) 2 else 1 }
println(array.asList())

val array = List<String>(5) { e -> if (e % 2 == 0) "even" else "$e" }
println(array.joinToString()) // Prints: even, 1, even, 3, even

// Loop array with indices
val swarm = listOf(5, 12, 15, 17)

for (i in 0 until swarm.size) {
    print("$i ") // 0 1 2 3 
}

for (i in 0..swarm.size - 1) {
    print("$i ") // 0 1 2 3 
}

for (i in swarm.indices) {
    print("$i ") // 0 1 2 3 
}

for (indexValuePair in swarm.withIndex()) {
    print("index: ${indexValuePair.index}, value: ${indexValuePair.value}\n")
} // Prints:  index: 0, value: 5