Double array java is a Java array with double values.
All values are stored in contineous memory location
Declaring double array in Java
General syntax to declare array is
dataType [] arrayName;
dataType: Any primitive or user-defined data types like int, char, float, double. etc
[] : notation to represent an array.
arrayName: name of an array;
double[] d;
double[] price;
here d and price are arrays that can refer to the array of double type.
Initializing and Accessing double array in Java
initialization specifies the size and initial values of an array.
Syntax of initialization is
dataType [] arrayName=new dataType[SIZE];
or
dataType [] arrayName=new dataType[]{value1, value2, …. ,value n};
double[] d=new double[5];
double[] price=new double[4];
above two statements will allocate memory for two array that are pointed by d and price.
Initialize both arrays by value 0.0 (the default value of double data type).
We can also provide some initial value to the array as follows
double[] d=new double[]{2.3,5.4,7.6,8.9,9.9};
public class MyDoubleArray {
public static void main(String args[]) {
double[] d=new double[]{2.3,5.4,7.6,8.9,9.9};
for(double a:d){
System.out.println(a);
}
}
}
2.3 5.4 7.6 8.9 9.9
another way to initialize array is
double[] d={2.3,5.4,7.6,8.9,9.9};
Java Array Loop Initialization
import java.util.Scanner;
public class MyDoubleArray {
public static void main(String args[]) {
double[] d=new double[5];
System.out.println("Enter the values for array");
Scanner sc=new Scanner(System.in);
for(int i=0;i
Enter the values for array
12.3
45.3
66.5
77.5
78.7
Array values are
12.3
45.3
66.5
77.5
78.7
Initializing Array using Arrays.fill()
Some times we need to fill array using same value that we can use fill method as below.
double[] d=new double[5];
Arrays.fill(d,4.4);
It will fill all array elements with 4.4
double[] d={2.3,4.5,5.6,7.8,9.8};
Arrays.fill(d,1,3,5.5);
Initializing Array using Arrays.setAll()
import java.util.Arrays;
public class MyClass {
public static void main(String args[]) {
double[] d=new double[5];
Arrays.setAll(d,(index)-> index + 1.1);
System.out.println(Arrays.toString(d));
}
}
Enter the values for array
[1.1, 2.1, 3.1, 4.1, 5.1]
DoubleStream to double Array in Java
DoubleStream is a sequence of double values that supports sequential and parallel aggregation operations.
DoubleStreams of() can be used to create a double stream of specified values.
toArray() of DoubleStream can use to convert it to an array.
import java.util.Arrays;
import java.util.stream.DoubleStream;
import java.util.Arrays;
public class MyClass {
public static void main(String args[]) {
DoubleStream ds=DoubleStream.of(7.5,66.7,88.7,333.4);
double[] d=ds.toArray();
System.out.println(Arrays.toString(d));
}
}
Enter the values for array
[7.5, 66.7, 88.7, 333.4]
double array Java length
The length of an array can be found using the length property.
public class MyClass {
public static void main(String args[]) {
double[] d={4.4,5.2,6.3,7.8};
System.out.println("Array Length "+d.length);
}
}
Enter the values for array
Array Length 4
double to double array copy
To copy one array in to another we can use
- clone()
- System.arraycopy()
- Arrays.copyOf()
there are other methods also we discuss above three here
double array copy using clone()
import java.util.Arrays;
public class MyClass {
public static void main(String args[]) {
double[] d={4.4,5.2,6.3,7.8};
double[] e=d.clone();
System.out.println(Arrays.toString(e));
}
}
array copy using System.arraycopy()
import java.util.Arrays;
public class MyClass {
public static void main(String args[]) {
double[] d={4.4,5.2,6.3,7.8};
double[] e=new double[d.length];
System.arraycopy(d,0,e,0,d.length);
System.out.println(Arrays.toString(e));
}
}
double array copy using Arrays.copyOf()
import java.util.Arrays;
public class MyClass {
public static void main(String args[]) {
double[] d={4.4,5.2,6.3,7.8};
double[] e=Arrays.copyOf(d,d.length);
System.out.println(Arrays.toString(e));
}
}
Above all will copy double array d to e.
Enter the values for array
[4.4, 5.2, 6.3, 7.8]
Sorting double Array
Arrays class provides a method sort() to sort any type of array.
example to sort double array is as below.
import java.util.Arrays;
public class MyClass {
public static void main(String args[]) {
double[] d={6.6,5.5,7.8,1.1,2.1,4.3,7.1};
Arrays.sort(d);
System.out.println(Arrays.toString(d));
}
}
output of above program is here
[1.1, 2.1, 4.3, 5.5, 6.6, 7.1, 7.8]
There are different ways to sort and array we discussed only one.