[java] Java ArrayList of Doubles

Is there a way to define an ArrayList with the double type? I tried both

ArrayList list = new ArrayList<Double>(1.38, 2.56, 4.3);

and

ArrayList list = new ArrayList<double>(1.38, 2.56, 4.3);

The first code showed that the constructor ArrayList<Double>(double, double, double) is undefined and the second code shows that dimensions are required after double.

1) "Unnecessarily complicated" is IMHO to create first an unmodifiable List before adding its elements to the ArrayList.

2) The solution matches exact the question: "Is there a way to define an ArrayList with the double type?"

double type:

double[] arr = new double[] {1.38, 2.56, 4.3};

ArrayList:

ArrayList<Double> list = DoubleStream.of( arr ).boxed().collect(
    Collectors.toCollection( new Supplier<ArrayList<Double>>() {
      public ArrayList<Double> get() {
        return( new ArrayList<Double>() );
      }
    } ) );

…and this creates the same compact and fast compilation as its Java 1.8 short-form:

ArrayList<Double> list = DoubleStream.of( arr ).boxed().collect(
    Collectors.toCollection( ArrayList::new ) );

double[] arr = new double[] {1.38, 2.56, 4.3};

ArrayList<Double> list = DoubleStream.of( arr ).boxed().collect(
    Collectors.toCollection( new Supplier<ArrayList<Double>>() {
      public ArrayList<Double> get() {
        return( new ArrayList<Double>() );
      }
    } ) );

Using guava

Doubles.asList(1.2, 5.6, 10.1);

or immutable list

ImmutableList.of(1.2, 5.6, 10.1);

You can use Arrays.asList to get some list (not necessarily ArrayList) and then use addAll() to add it to an ArrayList:

new ArrayList<Double>().addAll(Arrays.asList(1.38L, 2.56L, 4.3L));

If you're using Java6 (or higher) you can also use the ArrayList constructor that takes another list:

new ArrayList<Double>(Arrays.asList(1.38L, 2.56L, 4.3L));

Try this:

 List<Double> l1= new ArrayList<Double>();
 l1.add(1.38);
 l1.add(2.56);
 l1.add(4.3);

You are encountering a problem because you cannot construct the ArrayList and populate it at the same time. You either need to create it and then manually populate it as such:

ArrayList list = new ArrayList<Double>();
list.add(1.38);
...

Or, alternatively if it is more convenient for you, you can populate the ArrayList from a primitive array containing your values. For example:

Double[] array = {1.38, 2.56, 4.3};
ArrayList<Double> list = new ArrayList<Double>(Arrays.asList(array));

Try this,

ArrayList<Double> numb= new ArrayList<Double>(Arrays.asList(1.38, 2.56, 4.3));

ArrayList list = new ArrayList<Double>(1.38, 2.56, 4.3);

needs to be changed to:

List<Double> list = new ArrayList<Double>();
list.add(1.38);
list.add(2.56);
list.add(4.3);