CODEWITHSUNDEEP
javahashmap
sujit
sujit

Reputation: 1

how to compare two hashmaps by their keys and list of values in java

I have two different hashmap with Map<String, ArrayList> format , how to compare key first and then comparing their values are same or not.

Upvotes: 0

Views: 4063

Answers (1)

Stephen C
Stephen C

Reputation: 719576

If you are simply trying to test if all keys and all values in the maps are equal according to the equals(Object) method, then this should work:

boolean equalMaps = map1.equals(map2);

If want to test that entries with the same key have equal values, then:

boolean equalValues = map1.entrySet().stream()
                          .filter(e -> map2.get(e.getKey()) != null)
                          .allMatch(e -> e.getValue().equals(map2.get(e.getKey()));

(Note: the above is not the most efficient solution possible. The filter eliminates cases where the key is not present in map2 which would otherwise cause the allMatch to fail.)

And there are other solutions for other tests that you may want to perform.

Note the above solutions assume that the value type's equals(Object) method has the right semantics for your vaguely stated "comparing their values are same or not" requirement.

Upvotes: 2

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