I am fairly new to java streams and wonder whether there is an easy solution using java streams to check if any element in array 1 is also present in array 2
example:
array1 = ["banana","apple","cat"]
array2 = ["toast","bread","pizza","banana"]
--> return true
array1 = ["banana","apple","cat"]
array2 = ["toast","bread","pizza"]
--> return false
Thanks!
Just use Collections.disjoint. This method checks if any elements of the both arrays are common.
Collections.disjoint(Arrays.asList(array1), Arrays.asList(array2))
disjoint is that the method parameters are declared using wildcards, as such I can call it with Collections.disjoint(List.of(""), List.of(1)); - though Integer and String are completely un-related, this will still compile.
disjoint is allowed to throw a ClassCastException “if one collection contains an element that is of a type which is ineligible for the other collection.” (on my Java 9 it didn’t in your example).static <T, U extends T> boolean disjoint(List<T> left, List<U> right) { return false; } and use it as : disjoint(List.of(""), List.of(1)); this would not compile, but to my surprise, it does. One the other hand List<String> strings = List.of(""); disjoint(strings, List.of(1)); this does not. it seems like the compiler infers List.of("") to a type that we can't normally createList<Serializable> for List.of("") and List<Integer> for List.of(1), so that compiles. In the latter example you specify List<String>, so that doesn’t compile. We can of course control the type, for example List.<Object>of("").javac --debug=verboseResolution=deferred-inference ..., but I don't get a clear picture of what List.of("") is inferred to.I think this works for you. However, I had to convert the second array to a set check if element exists in an array. I think that's more intuitive than a for loop iteration.
String[] arr1 = new String[]{"a", "b"};
String[] arr2 = new String[]{"a", "d"};
Set<String> strings = Set.of(arr2);
boolean result = Stream.of(arr1).anyMatch(strings::contains);
Set for faster look-ups, since java-9 there is that one single method call Set::of, in java-8 - you would still need to do new HashSet<>(Arrays.asList(array))