CODEWITHSUNDEEP
javacollectionshashmap
Jenny Rose
Jenny Rose

Reputation: 131

Store two values in HashMap value

I want to store two values in hashMap's value field.

For example:

Key = 100, Value = 10, 20

I want to store in a way so that I could modify hashMap Value value using key ?

Lets say If I want to modify 10 to 30 then entry in map would be 

Key = 100, Value = 30, 20

Any way so that I could control both Value values independently using key of hashmap ..?

Upvotes: 1

Views: 105

Answers (3)

Rogue
Rogue

Reputation: 11483

I would also advocate using #computeIfAbsent:

Map<Integer, List<Integer>> map = new HashMap<>();
List<Integer> values = map.computeIfAbsent(100, k -> new ArrayList<>());
values.add(10);
values.add(20);
//100 -> [10, 20]

You can abstract the #computeIfAbsent call behind a method to ensure you always have a valid list value.

Upvotes: 0

Rajan Singh
Rajan Singh

Reputation: 324

Map<Integer, Set<Integer>> dualValueMap = new HashMap<>();
    Set<Integer> s1 = new HashSet<>();
    s1.add(10);
    s1.add(20);
    dualValueMap.put(100, s1);

Upvotes: 1

i.bondarenko
i.bondarenko

Reputation: 3572

You could use com.google.common.collect.Multimap

Example:

Multimap<Integer, Integer> map = ArrayListMultimap.create();
map.put(100, 10);
map.put(100, 20);

Upvotes: 1

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