How return sublist of items in first list that not exist in second list?

Question

Android 4.4

suppose I has 2 lists. I need to return sublist of items in first list that not contain in second list.

E.g:

[1,2,3,4,5] - [1,2,3,4,5] -> return []

[1,2,3,4,5] - [1,22,3,4,5] -> return [2]

[1,2,3,4,5] - [6,7,8,9,10] -> return [1,2,3,4,5]

[1,2,3,4,5] - [1,2,3,4,5,6] -> return []

[1,2,3,4,5] - [6,7,8,9,2] -> return [1,3,4,5]

How I can do this simple? I can write custom java method to do this. But maybe already exist any good solution.

I need this because I need to remove all items from first list that not contain in second list.

Thanks.

I need to remove all items from first list that not contain in second list — Alexei, Nov 18 '18 at 13:33
Yeah I get that. What have *YOU* tried to solve *YOUR* problem? — Nicholas K, Nov 18 '18 at 13:34
I use DB and if I first remove ALL items from first list it's start long DB operation. I need delete ONLY not exist items. — Alexei, Nov 18 '18 at 13:35
Possible duplicate of [How to do union, intersect, difference and reverse data in java](https://stackoverflow.com/questions/3590677/how-to-do-union-intersect-difference-and-reverse-data-in-java) — RubenDG, Nov 18 '18 at 13:40

score 1 · Accepted Answer · answered Nov 18 '18 at 13:35

1

You can use List.removeAll(Collection) :

List<Integer> listFirst = ...;
List<Integer> listSecond = ...;

List<Integer> listThird = new ArrayList<>(listFirst);// use of 3rd list to keep the 2 others
listThird.removeAll(listSecond);

answered Nov 18 '18 at 13:35

azro

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How return sublist of items in first list that not exist in second list?

1 Answers1