Kotlin study notes

Record your learning journey from today:kotlin

Today's date is 2019.4.21. This is the first time I write a blog since learning programming. Although it is a personal idle note, it is just to deepen my understanding of programming. And understanding of programming
Today I learned arrays from kotlin. If I have misunderstandings about these, I hope God can point them out so that I can improve them

Three basic properties of arrays: consistency, order, immutability

Three ways to create an array of objects in Kotlin

arrayOf(vararg elements:T) where vararg indicates that the parameter is variable
arrayOfNulls<>(size:int) specifies the size of the array and creates an array with elements <>. Specifically because T<> cannot be writtenEnter it, so forgive me.
array(size:int,init:(int)->T) constructor, specify the size of the array through size. init is a function to initialize elements, we generally use Lambda expressions later

For specific usage, we check the following code:

fun main(args: Array) {
//Static initialization
val intArray1 = arrayOf(21,23,24)
//Dynamic initialization
val strArray = arrayOfNulls(4)
//Initialize the elements of the array
strArray[0] = "Zhang Fei"
strArray[1] = "Guan Yu"
strArray[2] = "Liu Bei"
strArray[3] = "Liu Guan Zhang"
// strArray[4] = "subscript out of bounds"/because the array length is specified. So immutable -> prompt error. subscript out of bounds
//traverse string array
for (item in strArray.indices){
println(strArray[item])
}
val intArray2=Array(10){i->i + i}
// Traverse the intArray array
for (item in intArray2){
println(item)
}
}

The problem we often encounter: subscript out of bounds:Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException

This is the end of today's study. I hope I can continue to write the article on CSDN and cheer for myself!!