我有一组字符串
val set = HashSet<String>()
set.add("a")
set.add("b")
set.add("c")
我需要将它转换为数组。
val array = arrayOf("a", "b", "c")
使用扩展函数 toTypedArray
如下所示:
set.toTypedArray()
该函数属于Kotlin库。
/**
* Returns a *typed* array containing all of the elements of this collection.
*
* Allocates an array of runtime type `T` having its size equal to the size of this collection
* and populates the array with the elements of this collection.
* @sample samples.collections.Collections.Collections.collectionToTypedArray
*/
@Suppress("UNCHECKED_CAST")
public actual inline fun <reified T> Collection<T>.toTypedArray(): Array<T> {
@Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN")
val thisCollection = this as java.util.Collection<T>
return thisCollection.toArray(arrayOfNulls<T>(0)) as Array<T>
}
只需使用val array = set.toArray()
类型不匹配。需要:Array<String>,找到:Array<(out)Any!>!
- Abner EscócioArray <(out) Any>!
,没有任何问题。 - user8959091你可以直接调用
val array = set.toArray()
已测试通过 Kotlin 1.2.51。
将 Set(HashSet) 转换为数组
import java.util.*
fun main(args: Array<String>) {
val set = HashSet<String>()
set.add("a")
set.add("b")
set.add("c")
val array = arrayOfNulls<String>(set.size)
set.toArray(array)
println("Array: ${Arrays.toString(array)}")
}
Array: [a, b, c]