You might want to consider using a Collection
implementation instead of a flat array.
The Collection
interface defines a contains(Object o)
method, which returns true
/false
.
ArrayList
implementation defines an indexOf(Object o)
, which gives an index, but that method is not on all collection implementations.
Both these methods require proper implementations of the equals()
method, and you probably want a properly implemented hashCode()
method just in case you are using a hash based Collection
(e.g. HashSet
).
You can use one of the many Arrays.binarySearch()
methods. Keep in mind that the array must be sorted first.
With Java 8, you can do this:
int[] haystack = {1, 2, 3};
int needle = 3;
boolean found = Arrays.stream(haystack).anyMatch(x -> x == needle);
You'd need to do
boolean found = Arrays.stream(haystack).anyMatch(x -> needle.equals(x));
if you're working with objects.
Use a for loop. There's nothing built into array. Or switch to a java.util Collection class.
Source: Stackoverflow.com