DE
Java - convert double[] to List<Double> - primitive Double-Array in Objektliste
3 points
Problembeschreibung
xxxxxxxxxx1// Wir haben:2double[] arr = {1.2, 2.7, 3.9};3// Und wir wollen diese Array in eine List konvertieren: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]Ausgabe:
xxxxxxxxxx1
[1.2, 2.7, 3.9]Rückgabe der erforderlichen Implementierung z.B. ArrayList oder 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]Ausgabe:
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]Ausgabe:
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]Ausgabe:
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]Ausgabe:
xxxxxxxxxx1
[1.2, 2.7, 3.9]- Die beste Lösung -
DoubleStream.of(Java 8) DoubleStream.of+ ArrayList zurückgeben (Java 8)- Explizite Iteration über Array (before Java 8)
Doubles.asList(Guava)ArrayUtils.toObject(Apache commons lang3)
