I have following Java code,
int a[] = new int[] {20, 30} ;
List lis = Arrays.asList(a) ;
System.out.print(lis.contains(20));
However, output is false. Can anybody help me, why this is not giving True ?
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2 Answers
What you get is not a list of integers but a list of integer arrays, i.e. List<int[]>. You can't create collections (like List) of primitive types.
In your case, the lis.contains(20) will create an Integer object with the value 20 and compare that to the int array, which clearly isn't equal.
Try changing the type of the array to Integer and it should work:
Integer a[] = new Integer[] {20, 30} ;
List lis = Arrays.asList(a) ;
System.out.print(lis.contains(20));
2 Comments
Arpssss
Thanks a lot. Is there any other way to solve this ? Means convert array in such thus can use contains and delete method ?
Louis Wasserman
You can't solve it any other way without library support (or implementing a wrapper
List yourself), but if you use Guava, you can use Ints.asList(int[]) on an int[] directly.The static method asList uses as parameter varargs: .... Only by requiring <Integer> you prevent a List<Object> where a is an Object.
int[] a = new int[] {20, 30} ;
List<Integer> lis = Arrays.asList(a) ;
System.out.print(lis.contains(20));
