Example 1: Check if Int Array contains a given value

1. public class Contains {
3. public static void main(String[] args) {
4. int[] num = {1, 2, 3, 4, 5};
5. int toFind = 3;
6. boolean found = false;
8. for (int n : num) {
9. if (n == toFind) {
10. found = true;
11. break;
12. }
13. }
15. if(found)
16. System.out.println(toFind + " is found.");
17. else
18. System.out.println(toFind + " is not found.");
19. }
20. }

When you run the program, the output will be:

3 is found.

In the above program, we have an array of integers stored in variable num. Likewise, the number to be found is stored in toFind.

Now, we use a foreach loop to iterate through all elements of num and check individually if toFind is equal to n or not.

If yes, we set found to true and break from the loop. If not, we move to the next iteration.

Example 2: Check if array contains given value using Stream

1. import java.util.stream.IntStream;
3. public class Contains {
5. public static void main(String[] args) {
6. int[] num = {1, 2, 3, 4, 5};
7. int toFind = 7;
9. boolean found = IntStream.of(num).anyMatch(n -> n == toFind);
11. if(found)
12. System.out.println(toFind + " is found.");
13. else
14. System.out.println(toFind + " is not found.");
15. }
16. }

When you run the program, the output will be:

7 is not found.

In the above program, instead of using a foreach loop, we convert the array to an IntStream and use its anyMatch() method.

anyMatch() method takes a predicate, an expression or a function which returns a boolean value. In our case, the predicate compares each element n in the stream to toFind and returns true or false.

If any of the element n returns true, found is set to true as well.

Example 3: Check if array contains a given value for non-primitive types

1. import java.util.Arrays;
3. public class Contains {
5. public static void main(String[] args) {
6. String[] strings = {"One", "Two", "Three", "Four", "Five"};
7. String toFind = "Four";
9. boolean found = Arrays.stream(strings).anyMatch(t -> t.equals(toFind));
11. if(found)
12. System.out.println(toFind + " is found.");
13. else
14. System.out.println(toFind + " is not found.");
15. }
16. }

When you run the program, the output will be:

Four is found.

In the above program, we’ve used a non-primitive data type String and used Arrays‘s stream() method to first convert it to a stream and anyMatch() to check if array contains the given value toFind.