This is the code I have right now
public class removerDuplicados<T> {
public removerDuplicados() {
}
public T[] removerDups(T [] arr) {
T[] res = Arrays.stream(arr).distinct().toArray();
return res;
}
}
But this line
T[] res = Arrays.stream(arr).distinct().toArray();
Gives me incompatible types error
Interestingly enough, you can't do this particular trick with collections, where types are erased, but you can with arrays:
// this method can be static
@SuppressWarnings("unsafe") // safe because we're getting the type from the array object
public static <T> T[] removeDups(T[] arr) {
// https://stackoverflow.com/questions/212805/in-java-how-do-i-dynamically-determine-the-type-of-an-array
Class<T> componentType = (Class<T>) arr.getClass().getComponentType();
return Arrays.stream(arr)
.distinct()
.toArray(size -> (T[]) Array.newInstance(componentType, size));
}
Try this. The copy is redundant, but it can be compiled without reflections, casting or warnings.
public static <T> T[] removerDups(T [] arr) {
return Arrays.stream(arr)
.distinct()
.toArray(n -> Arrays.copyOf(arr, n));
}
public static void main(String[] args) {
String[] array = {"a", "b", "a"};
String[] uniq = removerDups(array);
System.out.println(Arrays.toString(uniq));
}
output:
[a, b]
This will work. Just call removerDuplicados.removerDups( ARRAY_NAME )
import java.util.Arrays;
public class removerDuplicados<T>
{
@SuppressWarnings("unchecked")
public static <T> T[] removerDups(T [] arr)
{
return ( (T[]) (Arrays.stream(arr).distinct().toArray()) ) ;
}
}
Object[] is not a T[].
public static void main(String[] args) { Integer[] ints = { 1, 2, 3, 3, 3, 4, 5, 6, 6, 7, 8, 1 } ; System.out.println(Arrays.toString(removerDuplicados.removerDups(ints) )); }ints = removeDups(ints);. You'll get a ClassCastException. Your example works because T is Object.toArray.
T[] res = (T[]) (Arrays.stream(arr).distinct().toArray()) ;