Java: Count unique values in a Map

Question

In a `Map` I want to know how many unique values of `V` there are. Is there something like `getValueSet()` so that I can then get the size of this set? In pseudo code: ``` Map myMap = ...//initiate Map; Set valueSet = myMap.getValueSet() int numberUniqueB = valueSet.size(); ``` Unfortunately there is no `getValueSet` method. Alternatively I can iterate through the list myself like this: ``` Set mySet = new HashSet(); for(Map.Entry entry : myMap.entrySet()){ V value = entry.getValue(); mySet.add(value); } int countUniqueB = mySet.size(); ``` But this seems like I'm reinventing the wheel. Is there something in `Collections` or elsewhere that already does what I'm looking for? If not, is there a more efficient way to get the result than how I have it above?

Accepted Answer

Java 8 has been around a while now:

```
int count = myMap.values().stream().distinct().count();
```

Java: Count unique values in a Map

Solution

Problem