CODEWITHSUNDEEP
javajava-8java-stream
upog
upog

Reputation: 5531

Stream Iterate hashMap and process the data

I want to Iterate the hashmap using java Stream and would like to execute an inline function for each key and then sum the value

Map<Integer, Integer>  myMap= new HashMap<Integer, Integer>() {{ 
                put(5000, 0);
                put(1000, 10);
            }};

myMap.entrySet().stream().map(e-> {/* want to fetch the corresponding value and increment by X  and find the sum*/ });

Upvotes: 0

Views: 346

Answers (2)

pvpkiran
pvpkiran

Reputation: 27038

Try this. This should work.

final Integer sum = myMap.values()
                         .stream()
                         .map(value-> value + X)
                         .reduce(0, Integer::sum)

iIf you wish to get access to key, try this 

myMap.entrySet()
                .stream()
                .map(entry -> entry.getValue() + X) // you can use entry.getKey() to get access to key
                .reduce(0, Integer::sum);

Upvotes: 3

Thiyagu
Thiyagu

Reputation: 17890

Use mapToInt to generate an IntStream and sum to sum the mapped elements.

myMap.entrySet()
   .stream()
   .mapToInt(entry -> entry.getValue() + X)
   .sum();

Upvotes: 1

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