Check if Java Array contains a certain value

• In this tutorial see various ways to check if Java Array contains a particular value.
  Check if the array contains the value using linear search.

  public class TestArrayContains {
  
  	public static void main(String args[]) {
  		String[] values = { "AB", "BC", "CD", "AE" };
  		String testValue = "AB";
  		boolean contains = contains(values, testValue);
  		System.out.println("Does Array  contains value " + testValue + " is " + contains);
  	}
  
  	public static <T> boolean contains(final T[] array, final T v) {
  		if (v == null) {
  			for (final T e : array)
  				if (e == null)
  					return true;
  		} else {
  			for (final T e : array)
  				if (e == v || v.equals(e))
  					return true;
  		}
  
  		return false;
  	}
  
  }
  

• Check if the array contains the value using Arrays class and Java 8 input Stream

  import java.util.Arrays;
  
  public class TestArrayContains {
  
  	public static void main(String args[]) {
  		String[] values = { "AB", "BC", "CD", "AE" };
  		String testValue = "AB";
  		boolean contains = isArrayContains(values, testValue);
  		System.out.println("Does Array  contains value " + testValue + " is " + contains);
  	}
  
  	public static <T> boolean isArrayContains(T[] array, T value) {
  		return Arrays.stream(array).anyMatch(value::equals);
  	}
  
  }
  

• Check if the array contains the value using ArrayUtils.contains from Apache Commons Lang

  import java.util.Arrays;
  
  public class TestArrayContains {
  
  	public static void main(String args[]) {
  		String[] values = { "AB", "BC", "CD", "AE" };
  		String testValue = "AB";
  		if (ArrayUtils.contains(values, testValue)) {
  			System.out.println("Array contains" + testValue);
  		}
  	}
  }
  

• If the array is a int, double or long we can use these IntStream, DoubleStream or LongStream respectively

  import java.util.Arrays;
  import java.util.stream.IntStream;
  
  public class TestArrayContains {
  
  	public static void main(String args[]) {
  		int[] values = { 1, 33, 55, 66 };
  		int testValue = 33;
  		boolean contains = IntStream.of(values).anyMatch(x -> x == testValue);
  		System.out.println("Does Array  contains value " + testValue + " is " + contains);
  	}
  
  	public static <T> boolean isArrayContains(T[] array, T value) {
  		return Arrays.stream(array).anyMatch(value::equals);
  	}
  
  }
  

• If the array is sorted we can use the binarySearch method of the Arrays class

  
  import java.util.Arrays;
  import java.util.stream.IntStream;
  
  public class TestArrayContains {
  
  	public static void main(String args[]) {
  		int[] values = { 1, 33, 55, 66 };
  		int testValue = 33;
  		boolean contains = IntStream.of(values).anyMatch(x -> x == testValue);
  		System.out.println("Does Array  contains value " + testValue + " is " + contains);
  	}
  
  	public static int isArrayContains(int[] array, int value) {
  		return Arrays.binarySearch(array, value);
  	}
  
  }
  

  Check if the array contains the value converting it to Set

  
  import java.util.Arrays;
  import java.util.HashSet;
  
  public class TestArrayContains {
  
  	public static void main(String args[]) {
  		String[] values = { "AB", "BC", "CD", "AE" };
  		String testValue = "AB";
  		System.out.println(new HashSet(Arrays.asList(values)).contains(testValue));
  	}
  }
  

See Also
Spring Boot Interview Questions
Apache Camel Interview Questions
Drools Interview Questions
Java 8 Interview Questions
Enterprise Service Bus- ESB Interview Questions.
JBoss Fuse Interview Questions
Top ElasticSearch frequently asked interview questions