Is there a way to do something like this:
ArrayList<String>.removeAll(ArrayList<Integer>)
With the ArrayList<Integer> being the indices that I want deleted. I know that I could iterate through the indices list and use remove(index), but I was wondering if there is a one-command way of doing so.
I know how to put this iteration into one line, my question is, if there is a way implemented by oracle.
You can use a Stream to iterate through the indices to remove. However, take care to remove the highest index first, to avoid shifting other elements to remove out of position.
public void removeIndices(List<String> strings, List<Integer> indices)
{
indices.stream()
.sorted(Comparator.reverseOrder())
.forEach(strings::remove);
}
For removing from a list of Strings this will work, calling the proper remove(int) method. If you were to try this on a List<Integer>, then you will have to avoid calling remove(E) by calling .mapToInt(Integer::intValue) before calling forEach.
You can use Java 8 Streams.
For example:
IntStream.of(7,6,5,2,1).forEach(i->list.remove(i));
If the indices are given as a List<Integer>, you can do:
indexList.stream().mapToInt(Integer::intValue).forEach(i->list.remove(i));
Note that I preferred to use an IntStream and not a Stream<Integer>, since if you use a Stream<Integer> for the indices, if the list from which you wish to remove elements is itself a List<Integer>, calling remove(Integer) will remove the element whose value is that Integer, not the element whose index is that Integer.
indexList.forEach((index) -> { list.remove(i); }) at this point, no need to use a stream
int indices instead of Integer indices, to make the solution more general (otherwise it won't work if list was a List<Integer>).I still get warnings with the above by @rgettman. To avoid the warnings and to make sure you are using the right remove method you can do this. I know some people hate lambdas but I think this is clearer than the extra mapToInt
public void removeIndices(List<OtherObject> other, List<Integer> indices)
{
indices.stream()
.sorted(Comparator.reverseOrder())
.forEach(i->other.remove(i.intValue()));
}
removemethod for each index individually. All possible answers to your question will show such an approach.