如何用Kotlin创建一个数组，就像在Java中那样，只需提供一个大小?

How can I create a Array like we do in java?

如何像java那样创建数组呢?

int A[] = new int[N];

How can I do this in Kotlin?

在科特林我怎么做?

1 个解决方案

#1

According to the reference, arrays are created in the following way:

参照文献，数组的创建方式如下:

• For Java's primitive types there are distinct types IntArray, DoubleArray etc. which store unboxed values.

  对于Java的原始类型，有不同的类型IntArray、DoubleArray等，它们存储未装箱的值。

  They are created with the corresponding constructors and factory functions:

  它们由相应的构造函数和工厂函数创建:

  val arrayOfZeros = IntArray(size) //equivalent in Java: new int[size]
  val numbersFromOne = IntArray(size) { it + 1 }
  val myInts = intArrayOf(1, 1, 2, 3, 5, 8, 13, 21)
  

  The first one is simillar to that in Java, it just creates a primitive array filled with the default value, e.g. zero for Int, false for Boolean.

  第一个与Java中的相似，它只创建一个原始数组，其中填充了默认值，例如Int为0,Boolean为false。

• Non primitive-arrays are represented by Array<T> class, where T is the items type.

  非原始数组由数组 类表示，其中T是项类型。

  T can still be one of types primitive in Java (Int, Boolean,...), but the values inside will be boxed equivalently to Java's Integer, Double and so on.

  T仍然可以是Java中的一种类型原语(Int, Boolean，…)，但是其中的值将被与Java的整数、双精度等等进行等效的装箱。

  Also, T can be both nullable and non-null like String and String?.

  另外，T可以是空的，也可以是非空的，比如String和String?

  These are created in a similar way:

  它们以类似的方式创建:

  val nulls = arrayOfNulls<String>(size) //equivalent in Java: new String[size]
  val strings = Array(size) { "n = $it" } 
  val myStrings = arrayOf("foo", "bar", "baz")
  
  val boxedInts = arrayOfNulls<Int>(size) //equivalent in Java: new Integer[size]
  val boxedZeros = Array(size) { 0 }