Java Arrays Cheat Sheet

int[] arr1;

int[] arr2 = {1, 2, 3, 4};

int[] arr3 = new int[]{1, 2, 3, 4, 5};

int[] arr4 = new int[4];

arr4[0] = 1;

arr4[2] = 2;

arr4[3] = 3;

arr4[4] = 4;

int[] arr = new int[]{1, 2, 3, 4, 5};

System.out.println(arr[3]); // 4

System.out.println(arr[4]); // 5

arr[4] = 1;

arr[3] = 2;

System.out.println(arr[3]); // 2

System.out.println(arr[4]); // 1

String[] fruits = {"Apple", "Orange", "Grapes", "Mango"};

for (int i = 0; i < fruits.length; i++)
{
	System.out.println(fruits[i]);
}

String[] fruits = {"Apple", "Orange", "Grapes", "Mango"};

for (String fruit : fruits)
{
	System.out.println(fruit);
}

int[][] arr1 = new int[2][2]; // 2 row and 2 column

arr1[0][0] = 1;
arr1[0][1] = 2;
arr1[1][0] = 3;
arr1[1][1] = 4;

for (int i = 0; i < arr1.length; i++)
{
	for (int j = 0; j < arr1[i].length; j++)
	{
		System.out.print(arr1[i][j] + " "); // 1 2 3 4
	}
}

System.out.println();

int[][] arr2 = {{1, 2, 3}, {2, 4, 5}, {4, 4, 5}};

for (int i = 0; i < 3; i++)
{
	for (int j = 0; j < 3; j++)
	{
		System.out.print(arr2[i][j] + " "); // 1 2 3 2 4 5 4 4 5
	}
}

int[] arr1 = {3,5,1,2,8,6};
int[] arr2 = {1,2,3,5,6,8};
int[] arr3 = new int[3];

//Printing an array
System.out.println(Arrays.toString(arr1)); // [3, 5, 1, 2, 8, 6]

// Sorting an array
Arrays.sort(arr1);
System.out.println(Arrays.toString(arr1)); // [1, 2, 3, 5, 6, 8]

//Compares two int arrays lexicographically.
System.out.println(Arrays.compare(arr1, arr2)); // 0

// Returns true if the two specified arrays of ints are equal to one another
System.out.println(Arrays.equals(arr1, arr2)); // true

// Assigns the specified int value to each element of the specified array of ints.
Arrays.fill(arr3, 1);
System.out.println(Arrays.toString(arr3)); // [1, 1, 1]

//Copies the specified array
arr3 = Arrays.copyOf(arr1,4);
System.out.println(Arrays.toString(arr3)); // [1, 2, 3, 5]