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Java - convert double[] to List<Double> - primitive double array to list of objects
7 points
Problem description
xxxxxxxxxx1// We have:2double[] arr = {1.2, 2.7, 3.9};3// And we want to convert this array to list:4List<Double> list; // [1.2, 2.7, 3.9]
xxxxxxxxxx1
double[] arr = {1.2, 2.7, 3.9};2
List<Double> list = DoubleStream.of(arr).boxed().collect(Collectors.toList());3
System.out.println(list); // [1.2, 2.7, 3.9]Output:
xxxxxxxxxx1
[1.2, 2.7, 3.9]Return required implementation eg ArrayList or HashSet
xxxxxxxxxx1
double[] arr = {1.2, 2.7, 3.9};2
ArrayList<Double> list = DoubleStream.of(arr).boxed()3
.collect(Collectors.toCollection(ArrayList::new));4
System.out.println(list); // [1.2, 2.7, 3.9]Output:
xxxxxxxxxx1
[1.2, 2.7, 3.9]xxxxxxxxxx1
double[] arr = {1.2, 2.7, 3.9};2
List<Double> list = new ArrayList<>();3
for (double no : arr) {4
list.add(Double.valueOf(no));5
// we can also just add primitive double6
}7
System.out.println(list); // [1.2, 2.7, 3.9]Output:
xxxxxxxxxx1
[1.2, 2.7, 3.9]xxxxxxxxxx1
double[] arr = {1.2, 2.7, 3.9};2
List<Double> list = Doubles.asList(arr);3
System.out.println(list); // [1.2, 2.7, 3.9]Output:
xxxxxxxxxx1
[1.2, 2.7, 3.9]xxxxxxxxxx1
double[] arr = {1.2, 2.7, 3.9};2
Double[] doubleArray = ArrayUtils.toObject(arr);3
List<Double> list = Arrays.asList(doubleArray);4
System.out.println(list); // [1.2, 2.7, 3.9]Output:
xxxxxxxxxx1
[1.2, 2.7, 3.9]- Best solution -
DoubleStream.of(Java 8) DoubleStream.of+ return ArrayList (Java 8)- Explicit iteration over array (before Java 8)
Doubles.asList(Guava)ArrayUtils.toObject(Apache commons lang3)
