数组的初始化
一维数组
double[] myList =new double[10]; myList[0] = 1.1; double[] myList2 = {1.1, 2.2, 3.3,4.4,5.5,6.6,7.7,8.8,9.9,10.0};
二维数组
double doubles[][] = new double[2][]; doubles[0] = new double[2]; doubles[0][0] = 1.1; doubles[0][1] = 2; double[] t = new double[3]; doubles[1] = t;
与list的互相转化 和数组的流式处理
数组转list(java8流式处理)
发现错误: 基本类型的数组不能直接转list(使用方法)
List<Double> doubleList = new ArrayList<Double>();
//基本类型错误不能转list //doubleList = Arrays.asList(myList2); //doubleList = Stream.of(myList2).collector(Collectors.toList());
使用正常的方式
for (double x : myList2) { doubleList.add(x); }
list转数组(java8流式处理)
double[] arr = doubleList.stream().mapToDouble(Double::doubleValue).toArray(); //myList2
求和(java8流式处理)
double result = doubleList.stream().mapToDouble(ddd -> ddd).sum(); System.out.println(result);