Arrays.fill() in Java with Examples
Last Updated :
07 Dec, 2018
java.util.Arrays.fill() method is in java.util.Arrays class. This method assigns the specified data type value to each element of the specified range of the specified array.
Syntax:
// Makes all elements of a[] equal to "val"
public static void fill(int[] a, int val)
// Makes elements from from_Index (inclusive) to to_Index
// (exclusive) equal to "val"
public static void fill(int[] a, int from_Index, int to_Index, int val)
This method doesn't return any value.
Exceptions it Throws:
IllegalArgumentException - if from_Index > to_Index
ArrayIndexOutOfBoundsException - if from_Index a.length
Examples:
We can fill entire array.
import java.util.Arrays;
public class Main
{
public static void main(String[] args)
{
int ar[] = { 2 , 2 , 1 , 8 , 3 , 2 , 2 , 4 , 2 };
Arrays.fill(ar, 10 );
System.out.println( "Array completely filled" +
" with 10\n" + Arrays.toString(ar));
}
}
|
Output:
Array completely filled with 10
[10, 10, 10, 10, 10, 10, 10, 10, 10]
We can fill part of array.
import java.util.Arrays;
public class Main
{
public static void main(String[] args)
{
int ar[] = { 2 , 2 , 2 , 2 , 2 , 2 , 2 , 2 , 2 };
Arrays.fill(ar, 1 , 5 , 10 );
System.out.println(Arrays.toString(ar));
}
}
|
Output:
[2, 10, 10, 10, 10, 2, 2, 2, 2]
We can fill a multidimensional array
We can use a loop to fill a multidimensional array.
1)Fill 2D Array
import java.util.Arrays;
public class Main
{
public static void main(String[] args)
{
int [][]ar = new int [ 3 ][ 4 ];
for ( int [] row : ar)
Arrays.fill(row, 10 );
System.out.println(Arrays.deepToString(ar));
}
}
|
Output:
[[10, 10, 10, 10], [10, 10, 10, 10], [10, 10, 10, 10]]
2) Fill 3D Array
import java.util.Arrays;
class GFG {
public static void main(String[] args) {
int [][][] ar = new int [ 3 ][ 4 ][ 5 ];
for ( int [][] row : ar) {
for ( int [] rowColumn : row) {
Arrays.fill(rowColumn, - 1 );
}
}
System.out.println(Arrays.deepToString(ar));
}
}
|
Output:
[[[-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1]], [[-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1]], [[-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1], [-1, -1, -1, -1, -1]]]
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