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I am trying to figure out whether it is possible to print out an int ONLY if it is a value in an array of numbers. For example:

import java.util.Random; public class arrays { Random random = new Random(); public void method () { int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9}; int j = random.nextInt(20); if() { System.out.println("It is in the array."); } else { System.out.println("It is not in the array."); } } }

What I am not sure about is what you would put in the parentheses after the "if" in order for the System to print "It is in the array" ONLY if j is between 1 and 9.

Thanks!

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Use the java.util.Arrays utility class. It can convert your array to a list allowing you to use the contains method or it has a binary search allowing you to find the index of your number, or -1 if it is not in the array.

import java.util.Arrays; import java.util.Random; public class arrays { Random random = new Random(); public void method () { int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9}; int j = random.nextInt(20); if( Arrays.binarySearch(numbers, j) != -1 ) { System.out.println("It is in the array."); } else { System.out.println("It is not in the array."); } } }
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import java.util.Random; public class arrays { Random random = new Random(); public void method () { Integer[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9}; int j = random.nextInt(20); if(Arrays.asList(numbers).contains(j)) { System.out.println("It is in the array."); } else { System.out.println("It is not in the array."); } } }
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I tried to do this but no matter what number j is (I added "System.out.println(j);" so I can tell what j is), I get "It is not in the array" even when it is. Any idea why? Thanks.
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Arrays.asList(numbers).contains(j)

or 

ArrayUtils.contains( numbers, j )
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Since your array is sorted, you can use Arrays.binarySearch which returns index of the element if it is present in the array, otherwise returns -1.

if(Arrays.binarySearch(numbers,j) != -1){ system.out.println("It is in the array."); } else { system.out.println("It is not in the array."); }

Just a faster way to search and you also don't need to convert your array to list.

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