Java从ArrayList中删除哈希图，如果它不包含某些键集

Question

Let's say I have arraylist of Hashmap, and Hashmap contain some keys and values

Arraylist d = [{key1=1,key2=2},{key1=1,key3=3}]

I want to remove hashmap that does not contain certain key. for example, I want to remove hashmap that does not have key2.

result should be:

d= [{key=1,key2=2}]

How do I approach this?

Answer 1

If source is

List<Map<String, Integer>> list;

You can filter it that way:

List<Map<String, Integer>> newList =
         list.stream().filter(m -> m.containsKey("key2")).collect(Collectors.toList());